Customers text the year, make, and a screenshot of a check-engine light, and figuring out who needs what turns into a tangle of threads.
Customers can submit their vehicle and issue with the booking so each request is recorded in one workflow. You drive across town with the right parts, and the car's gone, the keys are missing, or nobody's home to meet you.
Require a deposit and send reminders before you roll out so customers commit up front and can confirm the appointment. You order parts on your own dime, finish the repair, then wait on a check while you're already out the cost.
Collect a deposit toward parts, then record cash or email a card invoice when the repair is done. Track payment status in one place.