Toilet leaks 4-6 months after wax ring replacement
Get something like this http://www.amazon.com/dp/B00KHSLV2G or this http://www.amazon.com/dp/B000BQUJEA (there are other types, those just came up first when I searched).

In case the links break: They are wax ring alternatives that are made of flexible plastic instead of wax, so they can take some movement without leaking. There are a bunch of different types with lots of different designs. I have never used them so I can't recommend any particular one.