1 pointAn "old timer" told me he leaves it on to scare away potential break ins when the shop is closed. The thought process is the would be thief would here the radio and think someone is still inside.
1 pointOne can often make more money charging what you are worth on fewer cars than giving your work away and hoping to make it on volume. IMO No skilled customer service driven shop should be charging less that $125.00 per hour and less that 75% mark up on parts, period. On higher cost parts it should be the shop owners decision on the mark up. Alway's give the customer their car back with the complaint fixed, washed,vacuumed and a discount card with a $2.00 bill under the fuel fill lid.