If you are maintaining your bounced emails manually, it is important to remove any hard bounces immediately. Hard bounces are bounced emails that result from an unfixable issue, such as the email address doesn't exist. Remove these from your list right away to ensure your list stays clean and sendable.
If you are receiving soft bounces, you may continue to send to these as they are caused by temporary issues, such as the recipient's email inbox is full. However, if the same email address is constantly sending back bounced emails, it is wise to remove this address as well as it is unlikely to become sendable again.
If you want assistance in managing your bounced emails, try SimplyCast. With SimplyCast's email platform, all hard bounces are removed automatically and soft bounces are removed after five unsuccessful sends.