lol i pay the 3 dollar a month insurrance on my bill that covers my 2 dvrs and modem. (on top of the rental fee)
i can break them a million times if i want, and its a simple trade in.
if i want a different model, its as simple as walking it into the comcast store, no need to explain why i am doing it or even let them know ahead of time.
its a sweet deal. buying hardware from your isp is for idiots lol