After the payment you get the access to our customers area where you can download the packages for 15 times each. That means you have the ability to download 15 updates in the future. Since all our add-ons are in the fully tested study right now, we are doing upgrades rarely and only fixing critical mistakes. There may be about 5-6 updates per year.
So I wouldn't say the license is for the lifetime, however it is for a very long time, and actually you choosing this time.
You don't have to renew the payment yearly, that's right.