How do I tell my;;;;;;;;;;;;;;;;;;;;;;;;;?

I actually know someone who is the same way as your uncle. He calls you because you are probably the quickest and most reliable person he knows who will come and fix his problem, so don't be so quick and reliable. The next time your uncle calls make up some kind of excuse of how busy you are and it may be a couple of days before you can make it over to his house. If it's really important to him he'll most likely find someone else maybe in his neighborhood who might be able to help him. Then in a couple of days give him a call and see if he still needs you to come by. Just give it a try and see what happens. The point is not to make yourself so easily available.