Check out this Rossen Report!  Next time you call your repairman, you’ll think twice to double-checking his efforts.  

How do you do that?  There are several things you can do:

1. Get three estimates!!!!  Always.  I’ve learned the hard way just because someone recommends someone, it doesn’t mean the person they recommend is honest.
2. Follow the repairman to the unit, watch him do everything!   Don’t turn your back on him.  This makes it harder to pull shenanigans at times. It also puts pressure on him or her that you are not trusting.  A good guy won’t care.  A shyster will.
3. Be courteous, but keep your mouth shut.  The more you talk, the more you will reveal what you do and don’t know–a repairman’s dream!
4. When the repairman says what he thinks is wrong, have him write it down and then go read about it online.  There are many forums that will teach you what is going on! 
5. Once you have a basic understanding about your problem from reading online, talk to the repairman about the repairs. Ask him educated questions.  See if he answers knowledgeably, patiently and professionally.  You don’t know how many times I find out what the repairman says versus what I read online do not jive!  It catches a lot of liars! 
6. If the repairman is arrogant or put off by your behavior–he’s not your guy.
7. Always ask for the parts you had replaced back once they are removed.   I do this for several reasons.  First, its my part, I own it.  Second, its proof that I have a defective part, if it is defective.  If I find out its not defective later, I can always sell it instead of the repairman. Why give him the extra money?  Just be sure you don’t ask for the part up front or he could switch your part for a junk piece if it has value.