While the drain connection for a garbage disposal is nearly universal and fits standard sink drain holes of 3 1/2 to 4 inches, the size of the disposal unit itself is not. You must have enough space in the cabinet underneath your sink to accommodate the disposal's housing. A larger model may not fit in a compact cabinet or if the existing plumbing is arranged in an unusual way. Before buying a new garbage disposal, measure the available space under your sink. If you are replacing an old unit, it's often easiest to choose a new model of a similar size.

These appliances do unscrew, but you need to disconnect everything properly when you replace your garbage disposal. Make sure you shut the power off to the area first and check that it’s off with a voltage detector. Disconnect the main drain line and P-trap, and then disconnect the dishwasher drain line if you have one connected. You can then unscrew your garbage disposal using a disposal wrench. Just make sure you disconnect the electrical lines before removing your appliance.

Never put glass in the garbage disposal. It can damage your disposal or eject shards of glass out of the disposal and cause injury. If you get broken glass in your garbage disposal, turn it off and cut the power from the breaker, use a tool like pliers or tongs to remove the glass, and use a wet-dry vacuum to remove the remaining glass pieces. If you can’t access the disposal safely, call a garbage disposal repair pro.

If the cost of repairing a leaking garbage disposal is close to the cost of replacing the disposal, then fixing the unit might not make sense. When deciding if you should repair or replace your garbage disposal, consider the age of your garbage disposal, the cost of the repair, and whether your garbage disposal has had other problems recently to help you decide if the cost of repairing the leak is better than the cost of replacing the disposal.