You may be able to install a garbage disposal on your own, especially if you're handy or have some experience with plumbing. However, if you have any concerns or want to make absolutely sure that the connections are installed correctly, you may be better off hiring a local garbage disposal installer to do the job. 

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. 

In some cases, it’s more cost-effective in the long run to replace a garbage disposal, but it depends on the specific issue you’re having and the age of your disposal. You should ask a garbage disposal repair tech for a quote to repair your appliance and then see if it would be more worthwhile to replace it. Additionally, garbage disposals last for around 15 years, so if you know your appliance is reaching that age, it’s likely better to pay for a new garbage disposal rather than sink money into repairs.

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.