If you have any confidence at all it is not hard to do. You just need to be sure to use the right equipment. If you can get your hands on the following things you can do it.
-Jewelers screw driver or micro screwdriver set
-Headset to magnify or some sort of magnification... not totally necessary if you are 20/20 but makes it allot easier
-Jewelers tweezers
-Lure lock box (find in fishing tackle or online) it has a sticky bottom and I have a full tray I disassemble and assemble everything small over it so when a screw drops it doesn't bounce....
If you have those things then just take care with the screws and don't be hasty to strip and scratch and you can change 95% of watch batteries
