Nailbook knows who is due, so the client who would have drifted gets a nudge at the right time.
Regulars slip through the gaps. Someone who came every three weeks quietly stops, and you do not notice until the chair is empty. Chasing everyone by hand is a job in itself, and it is time you could spend on creating your art.
Nailbook watches when each client is due back and shows you a list of exactly who to nudge, so the follow-up that fills next week actually gets done. When someone is due depends on the client, not a blanket rule.
It is Monday, and your reminders list shows five clients due this week, including one who usually comes every four weeks and is now at the fifth week. You tap their card, WhatsApp opens with a friendly message ready to go, and you click send. They are back in the chair by Friday.