Watches are useful if you need to know the time. If you are held up in a structure and need to know how much longer until daytime, then watches help. It also lets you know when you should go out to search, as daylight makes movement much easier. The watches are on 24 hour time. If you need to know the time without a watch, there are two ways of doing so. You can look at the sun or moon, and experienced players will be able to estimate the time. However, an easier way is to ask on the chat. If only one player responds he might lie though, but that rarely happens.