>>2021932>What makes an older bike worth restoring and upgrading?>level of qualityBasically, how expensive it was when it was new. Look up the level of the drivetrain components (all brands have a parts hierarchy for quality), and how nice the frame tubing / frame is. There are a number of other tells you will learn to see from a small blurry picture, but those are the simple ways.
>compatibilityMost nice 80s/90s bikes are fantastic projects because they're broadly compatible with a bunch of widely available cheap new and old parts. If a bike is pre 1988 or has campagnolo or french (simplex etc) components, it is maybe not a great basic project.
>conditionMost important is that the fork is not bent. Then that the wheels are actually in good condition, hub bearings and brake tracks and spokes, then that the chainrings are in good condition. Almost everything else is good to replace anyway if overhaul.
>fit It HAS to be in a good size for you, not just something you're adapting to make work.
>styleIt HAS to be in a colour you like, repainting is not worth it and if you don't like the colour get another bike, life is too short.
You're looking for stuff that has been ravaged by time rather than use, so it looks shabby but underneath is stuff which is not actually worn out. Also something which is complete and suits your use as it is. Imo the nice / practical builds tend to be fairly stock and for a classic road bike you'd just upgrade the brakes, make the gearing wider, and get nice consumables, but leave it mostly as it is if you can. Mtb doubly so, maybe even jsut nice bars. You're still buying new chain, cables, grips, brake pads, tires.
That cost adds up, it's like ~$200 to do a bike. It doesn't make sense relative to what you could sell it for (especially as you won't do a perfect job), but it absolutely can make sense if you keep the budget less than half the cost of an entry level new bike, and you've chosen a project which is quite nice
