Dont know that "clumping" on its own is the progenitor for assuming that burrs may be excessively worn. I think its more to do with the proportion of "dust" to "cuttings" that is a better indicator. Ideally your grinder should produce no (or very tiny amounts of) dust. If you grind a small amount of fresh coffee onto a white paper towel and then spread it out over the surface of the towel, you should be able to see that the vast majority of the ground coffee is made up of small cuttings, rather than ground-up dusty fines. If the opposite is true, then maybe the burrs are on the wrong side of worn and need replacing.
You can also tell by rubbing the freshly ground coffee between thumb and forefingers, it should have a sharp, edgy and gritty feel to it and when you brush it off your hands, there shouldnt be any fine dust remaining in the valleys of your fingerprints. All that being said though, you can buy a set of new burrs from CoffeeParts, one of our esteemed site sponsors for quite an innocuous amount of money and it may be worth doing. All the best,