Keep Your Twitter Account Active

To avoid having your account disabled or removed due to inactivity, log in and post an update within six months of your last tweet. Twitter determines inactivity using a combination of information, such as your last login attempt, the date of your last post and the date the account was created. You may not be able to tell if an account is inactive without logging in, as not all account activity is viewable by the public. Twitter removes inactive accounts in bulk, so as long as you log in at least once every six months and post an update, your account should be considered active. Writer Bio

How Long Does a Twitter Account Have to Be Inactive Before it Is Deactivated  - 56