If the unit (A/C compressor, furnace, water heater, etc) is older, but operated properly, I may put in about “near the end of its statistical life” verbiage.
BTW: My A/C compressor is a Craftsman, built in 1965, and it still works like a charm. I clean it every year (twice) and have only had it re-charged once.
Recently, I have my HVAC guy (I know, personally, both owners and they are really good and they pay for thier guys to get 40 hours of training every year) replace the blower on my furnace. In the paperwork, he stated “Recommend replacement of the furtnace”. It was 15 years old, lennox pre-cat 1 and operated properly and I asked the tech, why?
He siad that the furnace was OK, except for the blower motor he just replaced, but he also said that when the units are 15 years old or more, they always call out for replacement because if “liability problems”.
This is a very important point. I now tell this story to every client. What if you do an inspection and find everything working right, but the first furnace check-up the client has, the HVAC tech says that the unit should be replaced? Do you think you could get sued.
This actually happened to me once. The client called and was very angry. I canceled my inspection for that day (habded it off to anothe NACHI guy) and went up, asking for the client to have the HVAC tech there as well.
I re-checked the furnace. It was OK. The HVAC tech said it was not. I asked him why. He told me that the furnace was a conventionally drafted furnace and that was not energy efficient. I asked if the furnace, itself, was operatimg as designed. He said yes. So I said, "So, there is no defect, other than your feeling that it is not energy-efficient enough?. He said, “yes”.
I turned to the client and he started yelling at the tech, at which point the tech packed his stuff up and walked away.
Read and learn. You not only have to do your job properly, but also work to manage your client’s expectations.
Hope this helps;