if when you bought it it already had dust, then yes you probably should. If it has accumulated dust from your use, then no you shouldnt. to begin with, a new one is gonna probably end up the same way as your current one eventually. second, if you're not having any problems with it you should keep it because a fully functioning phone with a bit of dust is much more valuable than a non dusty one that has quirks. and third, just the principle of the matter. things are going to hapen. if you bought it and it got like that from regular use, you just deal with it. for example, if i buy a new car and on the third day it gets a chip on the hood from driving it, i dont take it to the dealer and say, "hey give me a new one. i drove it on the highway and a pebble chipped my paint".