If you use of email distribution you should allow for unsubscribes. The CAN-SPAM Act is a little vague on exactly when this is required, but the best approach to both stay out of trouble and show your respect for the people you are trying to engage with is to always offer a way to opt-out.
Email is a permission-based medium. Recipients are not required to accept your email and you cannot force them to do so. If you remove the unsubscription link and they want to unsubscribe, they’ll find another way. Either they’ll hit the spam button or they’ll block you (in today’s world the two are often synonymous), a far worse outcome than having them unsubscribe through your own process. The same holds true if you send an email after someone has opted out.
The easiest way all around is to use an email tool that supports an unsubscribe link. When clicked, the user’s email no longer receives the messages. A less optimal method is to ask recipients to reply to the message or a specific email address with an unsubscribe request. You need to couple this with a process to remove the person from the email distribution list.
If you use a link, it is important to test that it works. You need to verify that the link itself works and that the correct subscriber is successfully removed from the list. If you use a more manual process, it is important to occasional do tests to make sure that everyone involved is performing their tasks.
It’s hard to get excited about the unsubscribe process, but it is an important way that we demonstrate the integrity behind our communication. No one wants to lose a contact, but we need to remember that people have choices about who they want to connect with; they will choose the ones that respect them and honor their wishes.