I.m similar to most on this thread, when I had my last box (SF8) I jist let it ride, and never updated. But since I got my H2S, I frequently get asked to try stuff out for Wooshman and Benijofar, so they can be sure it works in all regions, how quickly a flash can be done and things like that, so I am constantly reflashing/ updating/ adding/ subtracting (I say constantly, but I may exagerate a little)
My motto was to leave it until it is broken, but now, like Kiddac, I have a rock solid backup from earlier in the year that I can fall back on if needs be.