"You did something to this truck about two years ago" is a question the shop should be able to answer in five seconds.
Customers hold their contact details, their vehicles, their full job history, their payments and their outstanding balances. Search by name, phone, plate or VIN and the whole history comes back.
Vehicles are records in their own right, so a car that changes hands keeps its service history. What was fitted, what it cost, who worked on it and when.
Customers can be marked tax-exempt, put on account terms, or given a store credit balance. Everything the counter needs to know is on one screen before the conversation starts.

Try it on your own work
Two weeks, everything switched on, no card. Put a real job through it and see whether the numbers come out the way you expect.
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