MountainAire05; Over the years I've replaced numerous (maybe a dozen and a half) compressors that I've purchased new from parts stores and auto dealers and have never had a warranty that was contingent upon having the dryer replaced. I'm not saying it's not a good idea rather, if the work to reapair the system was done in a timely manner, usually only the compressor, compressor oil and refrigerant has to be replaced. If all the refrigerant has leaked out, the entire system stands a good chance of being contaminated and then in addition to the dryer needing replaced, the expansion valve plus other parts might also need replacing.