I gave a customer an estimate today to replace a split system, I was very suprised at what I saw. The home owner had a Colemen split system with a gas furnace that was installed in May of 1970, and the system still ran. I live in NW Florida, most condersers do not last long because of the salt in the air. The home owner told me the only thing that had been done was the coils were cleaned a couple of times, a outside fan motor and 8oz of R22 last year. I got a laugh at what the home owner asked " A/C systems must have improved over the years, and new one should last even longer than this one did". Do you know ware I can buy one of those units that come with the 40 year parts/labor warranty? Laugh !