Checking pressures, re-charge and leak testing are usual procedures for this type problem. Did he do this?

Also he is resisting putting the quote in writing which I have asked him to do more than once. He was supposed to give a written quote on the day of his visit. He did not. Said he had to go check parts prices. Told him to email me. Three days later still no written quote but he wants to tell me the quote by phone. This is not how business is done. Any repairman of any stripe I've ever hired has given a written itemized quote on company letterhead.

He is the boss. One man show. I now have the quote for $812. You are saying this could be a much simpler repair than just replacing everything? Also if he did those tests he should have shown me or discussed with me about them right?

Couple of problems here. One is that he won't give you a written estimate. And he's saying 5 hours to do it? If he's charging by the hour than that's a little extreme. Typical sealed system job is 1.5-2 hours (where i work at least, and that includes built ins) But I won't say his estimate is too far off, approx 400$ for parts plus tax, plus refrigerant, plus labor (labor is what varies widely, my company would charge approx 275$ for this).

Also just because the guy was only there for a few minutes may not mean anything. If the evaporator has a hole in it visible to the eye or there is oil all over the suction line then you wouldn't need to hook up your gauges or take any other readings, it's a leak, it's visible and it needs to be fixed.

And checking system pressures/ recharging/ and leak testing is not typically done on a routine service trip. Unless the customer has agreed to pay for the additional cost to do said service.

I still disagree with the written estimate issue.

Also, if you're wondering about the compressor also needing to be replaced is because a lot of technicians believe that a leak in the evaporator causes moisture and contaminants to enter the system and end up in the compressor causing damage. I'm not going to give my opinion on that, just make sure if you do have a sealed system repair done that a new filter drier is installed.

And yes, he should show you how he came to his "diagnosis" as rich said.

Hopefully this helped.