Somebody sold that "oil change customer" a car,clothes,watch,sell phone,place to stay,etc. I figure it costs $100.00 each to get a new customer to brag about my shop. Give every oil change customer a reason to sell your shop to others. I would change oil with filter, hand car and clean windows, place $2.00 bill with discount card behind his fuel door and ask for their referrals. I keep track of all referrals. After years of doing this i a few customers just swing by for a free hand wash, fluid level and tire air checks. My co-worker scolded me for wasting my time. I then pulled up the "time wasting" customers account showing that in the last few years they spent $6k but referred $40k worth of work to our shop.