The difference between a helpful reminder and a nuisance is timing, frequency and who appears to be sending it.
Automated follow-up fails for social reasons, not technical ones. A message that arrives at 11pm, from an unnamed number, about an appointment the patient already attended, damages the practice more than silence would.
Three rules cover most of it: send from the chamber's identity, never more than the patient expects, and always with something useful attached — a report ready notice, a preparation instruction, a review date.
Build the sequence around the clinical journey, not the calendar. Post-procedure care, medication refill windows and annual recalls each deserve their own cadence.