A friend of mine lives in NC and his GF just had an AC experience. Started about a month ago, when the central AC was not cooling sufficiently. Setup is a condo with a gas furnace in a crawl space, plus 2 ton AC. AC part is 5 years old. She called an HVAC company, they came out, diagnosed it was low on charge, never even went to look at furnace half, probably because it was in the crawl space and they were lazy. So, they recharged it. In about a month, it was down, not working again.
So, this time that company plus at least one other, told her it's leaking, don't know where, not worth trying to find the leak, you need a new system. So, for $3500 she's getting a new 16 SEER. My thoughts on this are mixed. On the one hand, you'd think that they would at least go sniffing for the leak. If it's just the evaporator, a leaking braze joint, shrader valve, it could be fixed for what? Less than $1000 I would think. The HVAC guys have big incentive to sell a whole new system, but I can see other issues too. With a new system, they know it's solved. If they replace an evaporator, maybe it still has other problems too, and then what? Who eats the cost of the failed attempt, etc.....
If it was me, I would have insisted on looking for the leak, which as significant as it was, I would think would be easy to find. Bad thing here is that new systems don't seem to last long. As I reported here a month ago, the fancy ECM condenser fan on my 3 year old system just failed. Fortunately I was able to replace it with a conventional motor for $85.