You can continue to run the software indefinitely, regardless of whether you have active support and updates.
If you wish to purchase 12 months of support and updates, you need to renew the license and all official add-ons attached to it.
If you choose to renew the XF license but not the add-ons, they can be removed from your license, at which point you will have to uninstall them.
If you then wish to use them again in the future, you will nee to repurchase them.