The dumb watch battery.

Well, watch batteries do wear out too. I'm a cheap watch person, all it has to do is tell time, not make a fashion statement with the glitter of diamonds and gold. If it lasts 3-5 years that's good. Never spend more than $25.  But I do like a "water resistant" watch. And I have had several watches ruined by letting the people in a department store change the batteries and not getting them sealed back properly. Fortunately, many of these stores no longer offer to change a battery. Your best bet is to go to a jeweler. They carry the batteries, and the tool, to do it properly. Mine was changed in a snap for only $9.50. I have no need for a "waterproof" watch, and good thing. I also learned that these watches are pressurized, and special equipment is needed to open the waterproof watch. Never knew that.

If you need a watch battery, try one of your local jewelers. It may save your watch.