I hung my highest ever this year. It's at about 21 feet to the platform. The reason being is that it's in an are without much cover and deer trails coming from all around. So I went as high as I could in the tree I was using. Usually I go with about 12-17 feet. If the cover is good I go as low as I think I can effectively go. There's no reason to be at 25 feet when 12 is enough to properly conceal you. Let the land dictate how high you need to be.
-Jake