When it went out again, the warranty company actually put in a new compressor.

@Kevin Gorum  you can have a plumber do a pressure test on the supply side of the plumbing with an air compressor .  

Next time they come out have them do a leak repair before they add freon.It's an EPA violation to continue adding freon when you know there is a leak.Finally, the compressor may overheat on hot days due to clogged condense coils.

The current units are more than 30 years old and have the compressor on the garage wall.

While assessors look for improvements and make adjustments, for example, when I added an AC where the compressor was visible from the street, I got the letter explaining why my assessment was going up, they will not generally lower assessments without a request.Local practices vary.

@Byron W.The heat pump systems (external compressor, plus plenum heat exchanger) start around $3-3.5K CAD here ...

My inspector told me the HVAC compressor on the condo unit I was purchasing   wouldn't  make it thru the summer, so I purchased the warranty at closing.

I personally average out the repairs I would expect over the year based on how old items are within the house and understand that I cant anticipate what month each item might break down, so it would be foolish to take a single months expected repair cost as cashflow, when a repair could come up in november for 900 (I had a HVAC compressor need to be replaced) when I budgeted 1000 for annual repair costs.

That said, when it's working, it works fine.Problem: The compressor overheated and is more or less dead.

I read that it's possible with a compressor, to test the pipes for leaks?