Installing most apps won't slow your tablet, but some need to run all the time in order to be effective (for example, I have a weather app, a volume monitor, and a couple of other things that need to run continuously). Obviously, the more apps you have actually running, the less responsive your tablet will be. Whether or not you notice it will also depend on what processor you have in your tablet. If its one of those cheap Chinese jobbies, then it's probably pretty slow to start with.