If reminders are being sent and no-shows have not moved, the timing is the first thing to look at. It is more often wrong than the wording or the channel.
Too early
A reminder a week out is read, acknowledged, and forgotten. It has no effect on behavior on the day, and by the time the appointment arrives it has been buried by everything since.
Early reminders are useful for one purpose only: giving somebody enough notice to reschedule if they already know they cannot make it. That is worth having, but it is a different job from preventing a no-show.
Too late
A reminder two hours before is too late for the person to rearrange anything, and too late for you to fill the slot if they cancel. It converts a fillable gap into an empty one.
The shape that works
Three points, each doing a different job:
- On booking: confirm, and establish that changing it is easy.
- A few days out: long enough that a reschedule is useful to both sides. This is the one that generates the cancellations you can actually refill.
- Day before or morning of: the one that changes behavior on the day.
Skipping the middle one is the most common mistake, and it is the one that costs the most, because it is the only one that produces fillable cancellations.
Adjust for the business
Longer appointments and higher-value ones justify more notice, because the cost of an empty slot is higher and the rearrangement takes longer. Short, frequent appointments need less. First-time customers need more than regulars: they have less established habit around it.
If you have the data, look at when your own cancellations arrive relative to the appointment, and place the middle reminder just before the peak.
Check the obvious things too
Time of day matters. A reminder sent at 6am is read half-asleep. One sent at 8pm the night before is read properly. Anything after about 9pm is intrusive.
And time zones, if you serve more than one. A correctly-timed reminder in the wrong zone is a badly-timed reminder.
Test it
Change one thing, keep it for a month, compare the number. Reminder timing is one of the few things in a small business that is genuinely easy to test.