When you get to a certain age – or, perhaps more generously, to a certain level of maturity – it is a good idea to have a health checkup at least once a year to see how your body is holding up and what can be done to deal with any problems that have arisen.
IBM i applications have the same issues as people, as does all software running on any platform – although software is a bit different in that it can be replaced, renewed, rewritten, refurbished or simply left to rot in its swamp of technical debt.