Email can be a bit of a problem especially when you have an account that gets quite a bit of spam and junk email. At times it's easy to just make a new account and inform your contacts about your new email, but at other times you really need to continue using that email account. The only way to do so when you get hundreds of spam and junk email a day is using filters.
Thunderbird is a free open source email client. One feature that Thunderbird has is email filtering. This allows you to set some parameters and the program will follow those and do exactly what you tell it to do.
Go to Tools then Message Filters to bring up the options. Start a new filter to begin. Basically you have a couple options. If the top section's conditions are met, it will do what you want in the bottom section. For example, if you get the word Mercury in the body of an email, you can set a filter so that it goes into your Junk folder or anywhere else on your account. This can be set for words in the subject, body, email accounts, and many other options giving you full control.
If you have an account where you are getting twenty pieces of junk for every real email, it might be time to start also filtering out messages you want. Set up a filter for certain email addresses to go into a certain folder. This way you can filter out what you want and won't have to deal with the spam and junk as much making using your email a bit easier.
If you get creative, you can get to the point where even a junked email account that gets hundreds of spam messages a day is still usable under Thunderbird with the proper filters.