Sometimes a contact will call or email and state that they no longer want to receive emails from your company or organization.
Instead of deleting the contact, we recommend unsubscribing the contact from the list or setting the contact to "Do Not Email", which will block all future emails (regardless of whether they are subscribed to a list).
Deleting a contact might only temporarily stop the contact from receiving email, because if the contact is added or imported again in the future, they could receive future emails, which may cause CAN-SPAM compliance issues.
Keep in mind, CAN-SPAM requires contacts be able to unsubscribe for at least 30 days, so deleting contacts (or lists) before 30 days may violate CAN-SPAM. Per the FTC.gov website:
"Any opt-out mechanism you offer must be able to process opt-out requests for at least 30 days after you send your message."