There are many maintenance and repair issues that lead to a malfunctioning garbage disposal. Regular clogs place wear and tear on the motors, leading to an eventual shutdown. Electrical issues at the breaker, wall outlet, or disposal itself can fry the unit. The most common cause is simply a worn-down motor. These motors can only handle so much use before powering down for good. 

No, you do not need a garbage disposal to have a dishwasher. A dishwasher will work without one, and while it's rare to see a home with a dishwasher that doesn't have a disposal, it is possible. The two appliances pair well and are often installed together because a disposal simplifies meal cleanup.

However, your dishwasher should not be used as a replacement for a garbage disposal. Subjecting it to continuous food leftovers can lead to major clogs. If you choose not to install a garbage disposal, you should thoroughly rinse your plates or scrape excess food into the trash or a compost pile before loading them into the dishwasher to prevent plumbing issues.

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.

Garbage disposals can be considered bad for the environment due to their electricity usage, but good for the environment because they reduce the food waste sent to landfills. If everyone used a garbage disposal, it would tax the wastewater treatment facilities in that region, but if we had to choose one of the options, we’d say they are a net positive on the environment when used correctly.