I could get access to a lot of old and broken electronic equipment. Anything from shavers, radios to computer parts, and TV's.
How useful would it be to take these apart for parts to use in Arduino projects?
What kind of parts would be useful to extract, and is the time spent even worth it?
50 years ago I used to do this and ended up with piles of junk that was never used. Now, I wouldn't give it the time of day unless there was a particular component that I required. Having said that, I still take things to pieces and collect components just in case they might be useful - and periodically I throw out the complete collection in acknowledgement of its uselessness.
How useful the things are will depend upon your knowledge/experience and how well you can test components to make sure they still work and what their values are. Now the mechanical components such as motors, gears, etc... can be very useful.
However, even if you never use a single component from such salvage, you can learn a lot from how such things are put together.
I made this from old CD drives:-
I salvage things, even smd parts mostly for practice, although the leds, resistors, caps, inductors I've used often
its nice sometimes to find some cool ics or stuff like laser diodes, stepper motors that are fun to play with and all it it hurts your wallet less when it blows up from extensive educational fooling around
Anything with standard size resistors and stuff I try to strip out. Sometimes you need a specific value resistor, or what not for a project. I'm still really new to electronics so I've just been keeping everything, some of the stuff I don't even know what they are but could maybe come in handy once I do realize what it is. Resistors, capacitors and diodes are probably the most common. I live in Canada so it's hard to buy stuff like that here without ordering from the states, which ends up costing 100's of dollars in shipping and duty fees.