My father ran a garage, and my brothers were in the motor trade, so I grew up around motor vehicles.
A colleague bought a Rover 2000 when it was a new model. First service the garage charged for 6 plugs. Colleague asked for the extra two plugs. Shame faced service manager admitted the mistake and amended the bill.
Very many years ago, a neighbour had a Fiat 500. Regularly main dealer serviced, but a bad starter, until I set plugs, points and timing. The battery box was badly corroded, having had a "Replacement battery" fitted. The date stamp showed it to be older than the car!
About the same time, my wife's colleague's car ran short on oil.. The bill for the call out included a new rocker cover gasket, since the problem was that the leaking gasket was the original "Funny, you've billed me for a new gasket at every service" "Sorry Madam, No charge"
Many years later, my wife ran a Renault 6TL. Having had a new tyre fitted, by a national chain, I saw that the balance weights were almost all the way round the wheel and the valve was a tubeless one. Returned the car and told them that the wheels were not suitable for tubeless tyres and that a special adaptor was required to fit he wheels to the balancing machine., and would they please fit the correct tyre and our tube.
Wheel was returned with very few balance weights! One lost customer!
A neighbour went for a "Free track check" two weeks later noticed that the tyres were wearing and pointed it outb to him. I checked the track with my kit and found it to be out. Reset it, and the nuts went back to exactly where the dirt showed that they had been! originally
Exactly the same thing happened to the other next door neighbour!
Someone at work had their track Reset by the main dealer,. The front tyres wore out in 500 miles, and the fuel consumption was terrible! Took it back and told them to put it right and fit new tyres, at their expense. . OK after that!
Another neighbour bought his company car. next service "You need new rear discs sir" "Funny you changed them at the last service, that the company paid for" "Oh, so we did. Won't be necessary then"
According to main dealer, during warranty, (Not covered as "Wear and tear" ) our last cars needed new anti roll bar bushes and bolts. Never reported at any of the subsequent services, or MOTs, by two other garages, during the 12 years that we had them!
You have to watch out for the con artists.
Guess why I did all the servicing once the cars were out of warranty!
Howard