A booking goes in the diary weeks ahead, and by the time it comes round, it's easy to half-forget, especially if life's got busier since.
Either someone chases every booking by hand, which takes real time, or the business quietly accepts a certain amount of no-shows as the cost of doing business. It compounds: an empty slot from a no-show is gone for good, and if reminders aren't actually working, the same pattern of no-shows just repeats week after week.
Keep an eye on the calendar, notice what's coming up, and draft the reminder at a sensible time, written in your own voice, without deciding on its own that a booking should move.
Imagine no-shows dropping simply because reminders land at the right moment, in a voice that sounds like you, not a generic timer firing regardless of context.
There's an example of this here.
See exactly how the watching and drafting works, step by step.
See the example