Unless you made a really bad buy to start, no one rides it, had to buy a bunch of rare individual parts...it's worth it. Even then, if you ride, it's worth it. Comparable aluminum new fenders can set you back $50-100. Those Bluemels are dirt cheap at $70 for being old and classic.

Many times I think vintage and collectors only get into this because it's cheap, want it to be worth more, but wouldn't pay for it if it was. It's a catch 22.