What a deposit is actually for (and why 30% is usually wrong)
A deposit is not a payment plan and it is not a trust exercise. It is the price of your time if someone does not turn up.
Ask ten salon owners what their deposit is for and most will say “so people show up”. That is the effect, not the purpose. The purpose is narrower: if the client does not arrive, the deposit is what you are paid for a slot you could have sold to someone else.
Once you put it that way, the percentage stops being the interesting number. What matters is how replaceable the slot is. A 30-minute fringe trim at 16:00 on a Thursday can be refilled from the waitlist in an afternoon. A four-hour balayage at 10:00 on a Saturday cannot — that is the single most valuable block in your week, and losing it costs the same whether the client apologises or not.
Size it against the slot, not the service
A flat 30% across the price list quietly under-protects your expensive long appointments and over-charges the cheap short ones. The short ones are the appointments new clients try you with, and a deposit request is exactly the friction that loses them. Charge nothing on a fringe trim. Charge properly on the Saturday balayage.
A deposit is the price of your time if nobody arrives. Price the time, not the treatment.
The second thing to get right is the notice window, and it should be honest about your ability to refill. Twenty-four hours is the convention, but if your waitlist reliably fills a Saturday inside a morning then 12 hours is fairer and will lose you fewer bookings. If your work is booked three weeks out and never refills, 48 hours is defensible — as long as you say so before they pay, not after they cancel.
Whatever you choose, enforce it automatically. A policy you apply case by case is not a policy, it is a negotiation you will lose to whoever argues hardest — and your regulars, who never cancel, will be the ones who end up subsidising it.