How 'old' of a used aluminum-framed bike would you buy?
OK, OK; I know that's a tough question and maybe boils down to 'it depends' but I'm curious as to how old of an aluminum bike you would even consider. Sure, there's going to be lots of variables like how many miles on it, what kind of use/abuse, what brand and style of bike/frame, ..... . But it seems there would be a point where a certain number of years of age are going to make an aluminum-framed bike (let's not get into vintage steel, etc right now) probably not a serious contendor for a purchase because of general frame fatigue, as well as obsolete or older frame design and components.
At what point in number of years old would you not buy an aluminum-framed FS xc or all-mtn bike in well maintained (not beat, some scratches, all original components, 'average' use and mileage) condition even if the price seemed fair because you would be concerned about general metal fatigue and outdated components?