Yahoo gives users a certain amount of time to try to recover a deleted account, depending on the country of origin. For users in the United States, they can attempt to recover the account within 30 days.
Other country’s deadlines may be a little different. Australia-based users have 90 days, for example, while users in Hong Kong have 180 days. You’ll have to read Yahoo’s Terms of Service for your country to determine your deadline.
If you wait longer than your country’s deadline to try to recover the account, chances are slim that you can do so successfully.