Many major providers of free email addresses will delete an email account if it has not been accessed in a while, this depends on the provider.
Google's Gmail service is best known for keeping email accounts open after long periods of inactivity.
Microsoft will make an account inactive/delete an account after 270 days of inactivity. This means you should log into your Microsoft email account before this time period for it to remain active.
Yahoo will delete an account after roughly 365 days of inactivity. This means you should log into your Yahoo email account before this time period for it to remain active. Yahoo have created a guide on this here.
AOL reserve the right to delete an account after only 90 days of inactivity. This means you should log into your AOL/AIM email account before this time period for it to remain active.
You may be able to create the email address once again after it has been deleted if another user has not taken this email address up already! To do this you just need to create a new account with the same provider and attempt to give it the same email address that you previously had.
If you are unable to recreate the email address you once had, we recommend using a provider that does not typically delete email addresses after periods of inactivity.
If the email you have registered on your account was set up by an administrator at work/Uni/college and is no longer in use, you’ll need to contact us with as much detail about your account as possible, using the steps below:
2. When asked if you have access to the email address on record, select the No option
3. Complete the Account Recovery form with as much information as you can provide. We will investigate the account, and providing the information you've provided matches that on record, you'll be able to recover it with the minimum of fuss. Please remember the more information you can give us about the account, the better!