I believe that cold temperatures are what cause fishing lines to go bad. I've heard that if you are going to store your gear outside (like I'm sure many of us do), put your reals in a small cooler and your line will be fresh the next season. I don't know how much truth there is to that though. I imagin you would still want to peel off a few yards, to get rid of any damaged line. I would also think that keeping the gear indoors would prolong the life of your line.
My new frabil rod, I just spooled up with 2lb. test fireline with a 4lb. mono backing. That is my ultra light setup. On medium action clam, I have the same 4lb. Trilene I used for the backing on my ultra light. The line is from last year, and I'm thinking I may want to step it up to a 6lb. Test mono instead. I'm not sure what brand I want to get though, I might try that bionic stuff from northland. Or maybe a floroucarbon line.