Nothing lasts forever.
So far powder coat is beyond your budget correct? A arms, rear end housings, and suspension pieces dont need to be powder coated. You can source really nice pit free pieces from out west and paint them to look like brand new for less than powder coating your original pieces. Nothing on my frame is powder coated except for the core support. Everything was blasted, filled, epoxy'ed and painted.
Powder coat your frame if its a must, but the other stuff doesnt need it.