Although there are clocks that suit all room types, there are those that can't withstand excessive humidity or the possibility of unusually high temperatures. If you want your rectangular wall clock to do its job for as long as it's expected to, make sure you add it within a suitable environment.
Before you purchase the first rectangular wall clock that you find attractive online, consider first the ambient conditions of the area where you'll be placing the clock. For obvious reasons, there are rooms in our homes that tend to get colder or warmer than others. Some become drier or more humid as well.