This week a client of a Fairfax wellness clinic I work with missed her reminder texts. She didn't miss one of them. She got none at all. When I looked into it, the appointment reminders were working fine for almost everyone. They had a blind spot in exactly one place, and nobody would have found it by looking at a normal booking.
What actually happened
The clinic sends two reminders before every session: one a day before and one two hours before. For most clients, both go out on time. I checked several recent bookings and every one of them got both messages.
This client was different. She booked a session and then moved it to a later date seven minutes after booking. The reminders never followed the new date. She got no reminder for the original slot and none for the new one.
Nothing was broken in the usual sense. The reminder sequence started from the first booking. When the booking moved, the sequence didn't move with it.
Why rescheduling is the case that breaks reminders
Most people test their booking system the way a customer uses it on a good day: book, show up, pay. That path gets tested constantly, because almost every client takes it.
The edge cases get much less attention:
- A client reschedules, especially soon after booking.
- A client cancels and books again.
- Staff move an appointment on the client's behalf.
Each of these changes the booking after the reminders have already been set up. If the system doesn't treat the change as a fresh start, the reminders keep pointing at a time that no longer exists, or they go quiet.
The worst part is that it fails silently. There's no error and no alert. The only sign is a client who didn't get the message everyone else did.
How do you test your own appointment reminders?
You can do this in about fifteen minutes without any technical skill.
Step 1: Book a test appointment
Use your own phone number and email. Book it a day or two out.
Step 2: Move it
Reschedule it to a different date the way a client would, from the client's own link if you have one.
Step 3: Watch what arrives
Check whether the reminders arrive for the new time. Check that nothing arrives for the old one. If you only get confirmations and no reminders, you have the same gap.
Step 4: Repeat for a cancel and rebook
Cancel, book again, and watch the reminders a second time.
The same thing happens on other channels
The same week, a manufacturer I work with had its Facebook connection expire in the scheduling tool. Its scheduled posts failed for three days before anyone noticed. The tool kept the posts in its queue. The page simply stayed quiet.
Underneath, it's the same problem. The setup worked once, then something changed and nothing told anyone. Automation is very good at repeating the case you tested. It's much worse at telling you when the situation has changed.
What I'm doing about it
We aren't patching it in a hurry. The fix is planned for Monday, and the owner sees it once before it goes live. Over the weekend nothing changes, and the clinic team contacts affected clients in person. I'd rather take one careful day than replace one quiet gap with a new one.
Takeaway: your reminders have probably been tested on the bookings that go to plan, so spend fifteen minutes this week testing one that doesn't.
If you'd rather not run that test alone, I'm happy to walk through it with you.