R134A is dirt cheap these days and if you have the tools and find the leaks they are easy to fix. The hardest part for most folks is evacuating the system and charging it properly. I had to borrow a vacuum pump the first 3 times I did my AC on a vehicle but I finally got my own used for $40 it looks ugly but works just fine and is a larger pump. I also have a collection of Orings too and a spare valve or two and spare caps also seems I end up losing a cap on occasion working on the system in the past. Now the new cars have a new type of "freon" that requires new connectors and who knows what else I don't think you can buy the gas for it yet.More than a few years ago, I needed to put a can of freon into my car's AC (actually I think it was 134A, not freon). The following year I had to do it twice during the season, and the year after that, it needed it quicker. It was time to bring it to my mechanic, and have it fixed. He found a leak, and replaced not only the the particular part that was leaking but a number of others too. It cost me extra, but he didn't have an angry customer come back a year later when another part failed.