After you subscribe, you will get a response with instructions on how the list works, and perhaps most important, how to unsubscribe. You are expected to read and save these instructions. It is considered bad netiquette to send messages to the list requesting help in unsubscribing. Turn off the list when you go on vacation. It's like stopping your newspaper delivery.
Some lists have a vacation option.
For others, you have to unsubscribe, then re-subscribe when you return. A high traffic list can generate hundreds of messages a day and can overload your mailbox.