Re: Car Service
The difference is Bruce, you are using fixed price servicing, so it makes no odds what they do in your case.
Mup's garage are trying to charge her EXTRA to look at the a/c.
I don't want her or anyone else to be ripped off. Unscrupulous garages prey particularly on women and the elderly.
To address some points.
Drive belt - the compressor is driven via the main engine serpentine belt - there is no separate belt.
Air filter - the supply air goes through the main cabin filter, there is rarely if ever a separate filter for the a/c. If they are talking about the a/c filter (drier) there is no need to change this, unless the system has had a serious problem and is contaminated.
Condenser - simple 10 second visual check at the same time you look at the radiator.
Refrigerant charge - 10 second visual check if the system has a liquid line sight glass. If not, as long as there is cold gas going back to the compressor via the suction line, then the charge is ok. Again, 10 second check.
I know you did not mention this, but....
Re refrigerants - You are not allowed
to put 1234yf into a system designed for 134a and vice versa.
Any garage that tells you they need to retrofit the system to the new refrigerant are blatantly lying and breaking the law.