Not only during winter but in general. Some people, especially the elders don't drink water as they don't feel the need. That is really bad.
An app like this can help them a lot and in some cases even save their life. I see it has caffeine rules which is interesting. Maybe it tells me when to drink coffee or how much. I'd like to see who's going to respect that as addicts don't care. I know as I've been one till one and a half years ago.