I'm a bit of a newbie, so can someone explain why it's important to rotate boots with another pair? What's wrong with wearing them every day? Do they need time to breath between wearings for some reason?
Main reason: sweaty feet. Your feet give off quite a lot of moisture in the form of sweat. This is absorbed by the leather. Your boots need time to dry out between wearings.
Make sure you get some red cedar boot trees as well. The boot tree facilitates the drying process, keeps the form of the boot and makes them smell good as well.