My wife and I moved into our new home 5 years back. The Heating and A/C unit was around several years old. Ten years is a long time, but not too much in the Heating and A/C world. I read that with respected service it could live to be about 15 years old. Rather than hire out Heating and A/C service, I checked the Heating and A/C upkeep on our own. I cleaned, oiled and tightened all loose parts. I mucked out the condensate drain, washed the cooling coil and oiled the fan belt. I did it all and the Heating and A/C worked great. Last year our wife decided to have a Heating and A/C professional do the service. She read a blog on the importance of Heating and A/C repair done by a real licensed corporation. She insisted that the job needed to be hired out. I finally gave in and let her have the Heating and A/C professional come in. The Heating and A/C guy came and went. The Heating and A/C no longer worked after he left. On a 90 degree afternoon both of us did not have AC. I tried to repair the problem and couldn’t. I then had to call the guy back into our house and he told me our Heating and A/C unit was totally kuput. He couldn’t make a repair to save it. I needed to buy a brand new A/C device. I was livid to say the least. I ended up paying for A/C service, a brand new unit and babysitting the upgrade job because I didn’t trust the man. I have a brand new A/C unit and nobody but me will be touching it from now on.