We used to do frre brake checks at the shop.Then it came that we spent 3 to 4 hours a day at times doing free work.Then we got oh my buddy can do the brakes for nothing.So we started charging 20 bucks This was like 15 years ago.If they needed brakes we took the charge off.As said some places do oversell.I always tried not to push anything not needed.Alsao as stated people want free.Like diag time.Lets see back then scanner was over 2K plus upgrades Hads to have time to scan then have All Data etc Let alone the tech I have like 40K in tools that I had to buy.Yeah i liked when people said its nice the sahop buys you all those tools.Let alone they think iof labor is say 80 bucks an hour thats what you make.Ask how many would spend that much on stuff for work let alone testing for certs,school to keep up with new stuff etc.Oh yeah stand in water,snow,in and out hot and cold burn yourself cut your self etc.All for what less that 20 bucks and hour and it was lots less>Rocky