You wouldn't re-ball a console unless the syscon points to that being the problem. Even then it's hard to say if it's a BGA Issue or an RSX failure. Some people think the "pressure test" could help narrow that down. I've never had luck with that. Generally people don't re-ball a working unit as a preventative measure. Even retrofitting a 40/65nm shouldn't be done as a preventative measure. If your launch model runs, then most people will agree to just keep it dust free, with fresh thermal paste/pads and enjoy it until the time comes for rsx/token failure.