It took me 3 days to notice that my watch had stopped running. And I'd been wearing it for most of those 3 days. Is it weird that I don't look at my watch that much? Either way, I need to get a new battery fitted. I took it in to a jewelers today, and the price they quoted just for a battery replacement was outrageous - almost the cost of the watch itself. So I declined, and instead went home and ordered a very basic watch replacement kit from Amazon instead. I'll do it myself - I think (hope) it isn't too complicated. I think I just need to use the right tools to unscrew the back of the watch, and simply replace the battery (which I also need to order from Amazon). It'll probably end up being a lot less easy than that, especially with my very limited expertise when it comes to doing fiddly things, but we shall see.