Personally I would just keep on using your Amiga as you have always done. Obviously you shouldn't treat it like shit, but I can't see much point in leaving it in a cupboard. If you do that, it may as well be broken for all the use it will be. Amigas are meant to be enjoyed IMHO. It might be slightly "risky" to use it, but hey, getting out of bed in the morning is risky. Its a trade off.
Imagine how you would feel if you took your Amiga out of the cupboard one day and it didn't work? You'd be gutted because you left your beloved machine to die a sad, lonely death, not knowing the feeling of having a disk in it's drive and somebody playing with it's joysticks