well thats ok, hence running a server or pirating stuff. but considering how often they simply idle doing nothing i think its a waste of power. i admit that thermal creep over time can cause damage, one of the reasons why components have a predicted lifespan. even so, regular startups and shutdowns, most components would last about 5 years. i dont think i own any electronics over 5 years old. computers go obsolete in a year or two anyway, so why go to extreems to get an extra year of life out of something. creep in itself can usually be fixed by the "wiggle it" technique.
if you want hardware to last, there are better ways to do it than leave it on all the time. one good way is to avoid unneccisary tampering. esd damage can be undetectable for a long time before any noticeable damage sets in. another good way is to keep your computer area clean. i have to constantly clear dust and cat hair from my fans and intakes. smoking can be bad too. makes the dust sticky, as does humidity. im supprised computers dont have air filters. a secondary enclosure helps too, just so long as its ventalated. yes you can clean your case, but then thats tampering and can cause esd exposure, especially using an air compressor or vaccume. moving dust creates static, so use canned air with an anti-static agent. but if you can avoid dust collection in the first place, thats the preferable way. a good way to reduce dust collection, oddly enough, is to turn your computer off when not in use.
