Sometimes when I just have a spare evening and want to get my mind of off more important matters, I take a random PCB from my "junk bag" collected from some strange contraptions, and solder out everything that looks cool from it. That's how I got my hands on lots of totally rad, but also 95% totally useless ICs, some mysterious parts which I wasn't able to identify despite many sleepless nights spent digging through photos and datasheets, and some totally regular and common stuff, which was probably worth about 1/10th of the juice my soldering iron used in the process. Still, soldering is a nice way to heat up in winter, and the smell of fresh solder in the morning is something a true man will surely appreciate.
OTOH, a) you can get brand new samples for free in stock amounts from many vendors (YMMV), b) most of the stuff you'll get from disassembly will probably be worthless and/or neither reprogrammable nor refittable for any serious purpose, and you'll never know when they'll fail direly, requiring you to fix entire circuit that got reckd, c) some parts will get FUBAR during your "board games"... still, you'll probably learn how to solder efficiently after about 100 hours spent on desoldering/soldering them.
As a result, I have a nice box with lots of brand-new samples & fresh-from-the-shelf stuff, which I use for brand-new fresh-from-the-shelf ideas, and a bag of old junk, which I use for all those "it'll probably burn or explode... SO LET'S DO IT NOW!" ideas. I think (no citation nor hard proof here, sorry) that most people with some hobbyistic EE experience have a system similar to mine.
tl;dr the only real answer is, quoting zebonaut - maybe. If you're doing EE for money - don't bother with reuse even for prototypes or tests; it's essentially like asking for trouble. If you're doing it for fun though, the rule is
more trouble == more fun instead - so the answer is "Of course it's worth it, it still probably has the magic smoke inside!".