Recently purchased a Trek 820 steel frame and was wondering if could get some experienced opinion on how long this thing might last. Most likely, I'll probably upgrade to an aluminum frame when $ permits but was thinking about keeping this bike as a secondary for friends and relatives who might want to ride with me. Its not a high end steel by any means (just high tensile), but if I keep the paint pretty much on this thing and keep it clean, how long can a person expect it to last? I don't live in a salt air environment and probably won't be exposing it to too much hard elemant riding. Any info is most appreciated. Thx.