There are 2 types of plans: Subscription and Lifetime.
The subscriptions work over a specific period of time and allow you to use the software and get all the updates that come out during this period. At the end of the term, your license will be automatically renewed for an additional period, so that you can continue to use the software without interruption. See auto-renewal topic.
A lifetime license never expires and contains one year of free updates. After one year, you can continue to use the software of course, but you will no longer receive updates. At any time, you have the choice to renew 1 year of updates if you wish. See updates renewal topic.