Your booking becomes a job number in the form TAS 2026 0412, and that number goes at the top of a card that sits on the windscreen while your car is in a bay. Everything done to the car is written on it as it happens, by the person doing it.
On the card: every item checked and its state as green, watch or attend to; the measurements in millimetres rather than in words like a bit low; every part fitted with its price beside it; the hours; and the figure you were quoted on the telephone with the time of the call.
You keep the card. That single sheet is worth more than it looks, twice over. The first time is at collection, because a card written as the work happened cannot disagree with the invoice. The second time is next year, when somebody says your bushes have gone and you can look at what last year's card said about them.
Every card is copied into the office file under your registration. Ring up in three years asking what oil we put in and somebody can tell you.