The best time to send an SMS depends on the type of message. For marketing texts, most published guides point to late morning and early evening on weekdays. For appointment reminders, the evidence points to a different measure: the time left before the booking, with most reminders sent within 48 hours of the appointment. For service businesses such as air-con cleaners, this means setting a small number of timed messages around each job rather than looking for one perfect hour of the day.
This guide separates the types of customer SMS, sets out what the evidence says about each, covers the Australian rules that apply, and describes a simple way to test timing in a small business.
TL;DR
- Marketing SMS guides commonly recommend 9 am to 12 pm and 5 pm to 9 pm on weekdays. These are averages from other industries and need testing against a business's own customers.
- Appointment reminders are better timed by distance from the booking. Most reviewed studies sent them within 48 hours, and no single best practice has been established.
- A reminder 24 to 48 hours before a job, plus a short message on the day, suits most mobile service work.
- In Australia, ACMA requires consent, sender identification and a working unsubscribe option for marketing messages. A reminder that contains advertising can be treated as commercial.
- Timing should be tested by changing one variable at a time and tracking no-shows, reschedules and replies.
Table of Contents
- Why the answer depends on the message type
- Booking confirmations: send immediately
- Appointment reminders: time by distance from the job
- Quotes and follow-ups: keep them close to the enquiry
- Service and maintenance reminders: plan around the season
- Times and days to avoid
- Australian rules that affect timing and content
- How to test the timing
- The perspective of an air-con cleaning platform
- Setting up reminders in MyAirCare
- FAQ
- Sources
Why the answer depends on the message type
Most pages that rank for this question are written for retail and promotional campaigns. Their advice is consistent in outline: avoid very early mornings and late nights, and send during business hours or early evening. Figures vary between sources. One common range is 9 am to 12 pm and 5 pm to 9 pm; another favours 4 pm to 7 pm. Those differences show that the numbers depend on the audience, the industry and the offer.
An Australian bulk SMS provider makes a similar point: mobile phones are used most between midday and 6 pm, but the best time varies with what the message says. A discount offer, a booking confirmation and a reminder that a technician arrives tomorrow serve different purposes, so they need different timing.
For a trade business, four message types cover most needs:
- Booking confirmations, sent immediately after a booking.
- Appointment reminders, sent before the job.
- Quotes and follow-ups, sent after an enquiry.
- Service and maintenance reminders, sent months after a completed job.
Each is covered below.
Booking confirmations: send immediately
A confirmation answers the customer's question as soon as the booking is made: is it in? The message should go out within moments of the booking, at whatever hour the customer made it. Customers who book at 10 pm expect an instant acknowledgement, and holding it until morning adds uncertainty without any benefit.
The confirmation should state the date, the arrival window, the address, the service booked, the price or how the price will be set, and how to change the booking. A related guide covers how to run booking confirmation SMS within a week, and the email equivalent is covered in a booking confirmation email guide for air-con cleaners.
Appointment reminders: time by distance from the job
What the research shows
Reminders work. A study of 58,622 appointments at an Australian dental clinic found that introducing SMS reminders was associated with 14% lower odds of failed attendance and 15% higher odds of cancellation. The rise in cancellations is useful for a business. A customer who cancels in advance frees the slot, while a customer who does not appear wastes the visit. Further material on the effect of reminders is available in this overview of SMS appointment reminders for Australian businesses.
On timing, the evidence is less definite. A rapid review by Monash Health's Centre for Clinical Effectiveness found that most SMS reminders in the reviewed studies were sent within 48 hours of the appointment, and that no best practice for timing has been established. The same review reported that healthcare users preferred initial reminders within two weeks, with most preferring them within 1 to 6 days.
Two cautions apply. These are healthcare findings, and a clinic appointment differs from a home service visit. Also, the studies describe what was commonly done and preferred, not a proven optimum. They support a reasonable starting schedule, which should then be adjusted using the business's own results.
A starting schedule for mobile service work
For jobs booked days or weeks ahead, such as a split-system clean, a three-stage schedule is a sensible default:
| Message | When | Purpose |
|---|---|---|
| Confirmation | Immediately after booking | Confirm the details and give a way to change them |
| Reminder | 24 to 48 hours before the job | Prompt the customer to confirm, reschedule or cancel |
| Day-of message | Morning of the job, or when the technician is on the way | Give the arrival window and a contact number |
The 24 to 48 hour reminder sits inside the window most reviewed studies used. It is early enough for the customer to move the booking and for the business to refill the slot, and late enough that the booking is still in mind. For jobs booked more than two weeks out, a second, earlier reminder about a week before is a reasonable addition, consistent with the finding that users tend to prefer early notice.
The day-of message matters for trades because the customer often needs to do something: clear access to the indoor unit, secure pets, or be home to let the technician in. A short message that names the technician and arrival window reduces both missed access and phone calls to the office.
Time of day for reminders
No reliable evidence ties reminders to one clock time. A practical rule is to send during hours when most people expect to receive business messages, roughly 9 am to 6 pm on weekdays and a little later in the morning on weekends. A message that arrives at 6 am for a job two days away has no urgency to justify the hour. A message that arrives at 7 am on the day itself, saying the technician will arrive between 9 and 11, does.
One technical detail from an Australian provider: avoid scheduling messages exactly on the hour. Odd-minute send times such as 9:08 am are suggested to avoid clashing with alarms and other alerts. The effect is small, but it costs nothing to apply.
Templates for each stage are available in a set of appointment reminder templates for service businesses. The wider set of tactics for reducing missed jobs is covered in a guide on evidence-backed ways to reduce no-shows.
Quotes and follow-ups: keep them close to the enquiry
A quote sent to a customer who has just asked for one is a response. The same quote sent a week later is a cold approach. Prompt delivery matters more than clock time here. A quote should go out the same day as the enquiry, ideally within hours.
A follow-up can then be sent after a short gap, commonly one to three days, asking whether the customer has questions. One follow-up is usually enough. A second can be justified if the quote has an expiry date, but repeated prompts quickly become unwelcome and raise unsubscribe rates. Follow-ups are best sent mid-morning or early evening on weekdays, when customers are likely to be able to reply and make a decision.
Missed calls are a related problem. A customer who rings and reaches voicemail often contacts the next business on the list. A fast text reply, covered in a guide to missed call text back for Australian trades, should go out within minutes. This is a case where speed outranks any preferred hour.
Service and maintenance reminders: plan around the season
A service reminder is a message that prompts the next booking months after the last one. The Monash review and most timing studies concern appointments that already exist, so they say little about when to prompt a repeat booking. This is an area where no checked evidence is available, and the business's own records are the best guide.
Three practical principles apply to air-con cleaning:
- Anchor on the last job date. Many operators send a reminder about 11 months after the previous clean to prompt an annual repeat. Whether a business uses 6, 11 or 12 months should be tested against its own repeat rate.
- Account for the season. Air conditioners are used most in summer in most of Australia, and in the tropical north the dry season and wet season shape demand differently. A reminder landing just before the busy period is more likely to lead to a booking than one sent mid-peak, when the diary is already full.
- Use the slow season deliberately. A well-timed reminder in a quiet period can fill the diary with work customers would otherwise postpone.
A step-by-step approach to starting with a single automated message is covered in a guide on service reminder automation for trade businesses.
Times and days to avoid
Several timing rules hold across most sources and sit comfortably with Australian norms:
- Late night and very early morning. Messages outside roughly 8 am to 8 pm risk annoying customers and prompting unsubscribes. Transactional confirmations sent immediately after a booking are the exception, since the customer has just acted.
- Exactly on the hour. As above, odd-minute send times are suggested.
- Public holidays and the middle of a work meeting rush. Customers are less likely to read or act, and a reminder that arrives at the wrong time may be buried.
- Clusters of messages. Sending a reminder, a promotion and a review request on the same day lowers the impact of each.
The common question of whether 7 am is too early has no fixed answer. For a day-of notice about a technician arriving at 9 am, 7 am is acceptable and often welcome. For a promotion, it is likely to be seen as intrusive.
Australian rules that affect timing and content
Timing advice has to sit within the law. For marketing messages, ACMA states that senders need consent, accurate sender identification and an easy unsubscribe option. Unsubscribe requests must be honoured within 5 working days. The option must be free or cost no more than the usual address-use cost, must not require extra personal information or a login, and must work for at least 30 days.
Pure service messages are treated differently. ACMA notes that appointment and payment reminders, and messages about a service the customer already uses, are not commercial spam when they contain no advertising. The condition matters. A reminder that adds a discount or an upsell can become a commercial message, and the consent and unsubscribe requirements then apply to it.
Responsibility also stays with the business when software sends the messages. ACMA's position is that the sender remains accountable for consent evidence, identification and unsubscribe handling even when another provider delivers the texts. In practice, a business should keep a record of when and how each customer agreed to be contacted, and should keep reminders free of promotional content. A fuller checklist is set out in a guide to SMS marketing laws for Australian tradies.
How to test the timing
Published averages are a starting point. The attendance study of Australian dental appointments reported that attendance varied by demographic and time-related factors, and concluded that reminder systems may need to take these into account. The same applies to a trade business: customers on a Sunshine Coast rental, a Townsville home and a Brisbane office may respond differently.
A workable test uses these steps:
- Set a baseline. Record the current no-show, late-cancellation and reschedule rates over a month or more of jobs.
- Change one variable. Move the reminder from 48 hours to 24 hours, or from morning to late afternoon, but not both at once.
- Split the audience. Alternate customers between the two timings, for example by booking number, so that job type and season do not distort the comparison.
- Track the outcomes that matter. Confirmation replies, reschedules made in advance, no-shows and unsubscribes are more useful than open rates, which SMS does not report reliably.
- Run it long enough. A sole trader with 20 jobs a month needs several months to see a difference. Small samples mislead.
- Keep what works and repeat. Seasonal changes in demand mean results can shift, so the test is worth repeating once a year.
The perspective of an air-con cleaning platform
MyAirCare was built from first-hand experience of how air-con cleaning businesses actually run, and the view below comes from that.
We see timing as a scheduling problem, not a marketing one. The costly failures in this trade are a customer who is not home, a unit that is not accessible, and a booking that nobody confirmed. A reminder 24 to 48 hours ahead and a short message on the day address those directly. Hunting for the best hour of the day for a promotion matters much less.
We also think automation should remove the repetitive work without removing control. The sender should decide the schedule once, the system should apply it to every job, and the owner should be able to see what was sent. That matters for Australian trades in particular, because the business, not the software, carries responsibility under the Spam Act.
Finally, reminders are a growth tool as well as a protection. A service reminder that reaches a past customer before the next hot season is one of the cheapest ways to keep the diary full through a slow period. We would start with one message, measure it and expand from there.
— Lewis
Setting up reminders in MyAirCare
MyAirCare is booking and management software for Australian air-con cleaners. It includes online appointment scheduling, automated reminders, Stripe payments, quotes and invoices, and a mobile app for job tracking and rescheduling. Reminder timing is therefore set once and applied to every booking, instead of being sent by hand.
The Free plan costs $0 per month and is supported by booking fees. MyAirCare Pro is $199 per month. An AI phone agent add-on is also listed on the pricing page without a published price. There are no lock-in contracts. Details are on the MyAirCare pricing page, and the platform is described on the MyAirCare home page.
Other ways to reduce admin load are covered in a guide to three technology changes that cut admin time.
FAQ
What is the best time of day to send a text message to customers?
For marketing texts, many guides recommend 9 am to 12 pm and 5 pm to 9 pm on weekdays, but the figures differ between sources and industries. For service messages, the type of message matters more than the hour. A business should start within normal hours, roughly 9 am to 6 pm, and test from there.
How far ahead should an appointment reminder be sent?
Most SMS reminders in the studies reviewed by Monash Health were sent within 48 hours of the appointment, although no best practice has been established. A reminder 24 to 48 hours before a job, with a short message on the day, is a reasonable default. Jobs booked weeks ahead may also warrant an earlier reminder.
Is 7 am too early to send a text?
It depends on the message. A day-of notice that a technician will arrive at 9 am is generally acceptable at 7 am. A promotional message at that hour is more likely to cause annoyance and unsubscribes, so marketing texts are better held until later in the morning.
Do appointment reminders need an unsubscribe option in Australia?
ACMA treats appointment reminders with no advertising as service messages rather than commercial spam. If a reminder includes promotional content, it may become a commercial message, and consent, sender identification and an unsubscribe option are then required. Including an opt-out line in all messages is a safe practice.
Sources
- Best Time to Send Bulk SMS, SMS Broadcast
- An Investigation into Patient Non-Attendance and Use of a Reminder System, Journal of Dental Education
- SMS reminders rapid review, Monash Health Centre for Clinical Effectiveness
- Avoid sending spam, ACMA
- Dealing with spam, ACMA