The rebooking rate is the percentage of clients who walk out with their next appointment already in the diary. If 40 clients came through this week and 26 booked their next visit before leaving, the rebooking rate is 65%. It is one of the clearest early signs of client retention, because a client with a booking is very likely to come back, while one without has to remember, find the time and get in touch.
Measure it per person as well as for the business. Differences between stylists usually come down to habit: who asks, when they ask and how they put it.
In practice
A four-chair salon counts for a month. Stylist A sees 120 clients and rebooks 90 of them, or 75%. Stylist B sees 110 and rebooks 44, or 40%. Both have loyal clients. The difference is that A asks at the basin with a date in the question, and B leaves it to the desk after payment, when the client is already looking for her car keys.
The cheapest improvement is to ask earlier and more specifically. "Six weeks lands on a Thursday, morning or afternoon?" gets more yeses than "Do you want to book in again?" For clients who will not commit, a booking link sent by text the same day catches some of them later.
Follow every advance booking with a reminder text, since an appointment made six weeks out is easy to forget. The habit itself is covered in rebooking at the basin.