Are you seeing problems that were not there before? Or just concerned that problems might appear?
My own concerns had to do with things like the zoom lens getting stuck or the little buttons in the back starting to bounce and either require a hard press or generate two presses when you pressed only once. Mine is just two years old so I haven't run into any problems --- yet.
Actually I had problems with a six odd year old film camera with a lots of electronics (as opposed to gears and springs) inside. I started to get error codes in the readout and one day the camera would do nothing but display an error code. It was the failing of this camera that got me to buy a digital (Canon SD850 P&S).
Yes it is two more stops or four times the light output in order to double the distance using flash.
Digital camera hints:
Digital Camera Technicalia Made Easy