If your disposal grinds poorly, make sure that you are running enough water while operating the disposal and that you are not grinding materials that you shouldn't.

If you notice leaks below the disposal, pinpoint the source of the leak, and tighten the offending connection. If necessary, replace the drain gasket or the unit's mounting screws.

If the unit is unreasonably noisy, check to be sure that something hasn't entered the unit that shouldn't have. If all is clear, you may need to replace the blade, impeller, or motor; this should be done by a professional.

Because these types of repairs can be costly, it's often cheaper, faster, and wiser to replace the entire unit.