This was my exact thought... A couple of years is a good lifespan for any small computer electronics. If they need to be replaced after that then replace them. It would be very easy for a lightning strike or power surge/sag to kill these devices.

As for access points/routers remember that if you set the wireless mode to "B" only it will go further and through more stuff (instead of B/G). Your internet speed will be slower but you will have less signal drop as you move around.

Also as it was said above in the thread if you get a device with a external antenna pick up a set of high gain antenna which should help you get more distance as well.