Thank you @Glencoe some of them look plain cool to me, so far have checked 2-3 and all of them use different batteries so have to order probably random sets of batteries after making a list what I need!
If popping in a new battery won't work, then I doubt it will be worth your while paying to have it fixed, that is assuming a watchmaker will even be willing to work on it... Picture quality is too grainy for me to tell, but they look like some digital Casio's and such. There are plenty of brand new watches in the same style if you like that sort of style.
They are worth fixing if you would enjoy and wear them. For the price of a new battery you will be able to see if any other work is needed. There's a good chance most will fire right up. Let us know what happens.
When taking the back off keep track of any tiny springs that are used as contacts. An old shoe box as a work area will reduce the chance of tiny parts disappearing.
There's a channel on youtube, Vintage Digital Watches, the host goes way deep into repairing almost everything you can find wrong with just these sorts of watches. Excellent videos, I recommend watching them.
Much of the time, the watch just needs a new battery, and it wasn't worth the bother for the previous owner. But other things can go wrong as well. Screen fade, LCD bleed, missing segments are pretty common and sometimes fixable. Corroded battery terminals or traces are also common and sometimes fixable, and the corrosion residue can removed. Button contacts can be cleaned. Even broken traces and circuit boards can be fixed sometimes with very careful application of silver conductive paint or a tiny bit of solder.
Using his inspiration and techniques I recently repaired a BabyG (BGM100/module 1891), the quartz crystal contact pad had come detatched from the circuit board and required both silver paint and soldering a new wire, but now I have a watch with an alarm that plays "Bomboleo", so I'm very pleased.
If you're a fan of a particular watch, it can be fun to diagnose and repair it. The better quality digital watches are much more repairable (Seiko, Casio, Citizen and others), while some of the old digitals are kind of trashy on the inside, cheaply made.
If you're curious or you like them, give it a shot! You'll learn a lot and might find your next favourite watch, or be ready to fix it when it comes around.
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