All of the important info that I used to have mailed to me, I switched over to electronic format - Bank statements, credit card statements, cell phone bill, vehicle insurance, and a plethora of other things I can't remember at the moment.
Doing the above could help reduce the amount of mail that you get forwarded to you. THe only thing I can think of at the moment that requires some sort of physical address is vehicle registration, so if I were to hit the road and sell my house, I'd still need some sort of "address" for registration of the vehicles; meaning I can't totally go stealth and not have some sort of "address" to receive mail at.
