Your Community can certainly be open 24/7, all year round! We believe Community best practice is to enable users to connect, chat, and answer each other's questions at any time.
Many of our 135+ partner institutions, who use Community primarily for yield/conversion, will leave the Community open to allow students to continue the friendships they have made during their offer holder period, as they transition into university life.
Having said this, you can also opt to close your Community at the end of your student recruitment cycle; making it as easy as possible for you to manage.
We would recommend posting an Update to announce the closure of the Community a couple of weeks in advance - giving students a chance to swap contact details, make a note of items from their To-do list, or copy over key dates and reminders you may have pinned in Community groups.
You can then go to the Settings tab within the Community in question, and deactivate your Community. This means that students will no longer be able to access, but you will still have access to the data from that Community in your dashboard - the groups and their descriptions, all of the data on your Analytics from the lifecycle of that Community, and your User list.
You will still be able to export and filter that data, as well as duplicating an inactive Community - which will copy over your Community name and description, the groups and their descriptions and tags, and any chat settings. You can quickly and easily edit any of this, as well.