It will automatically re-activate if you're online after being away for a week or so, you won't notice anything different. It checks automatically if you ticked the box to remember your credentials. Very low maintenance (Unless their servers get hit hard again lol).
It's only if you take your computer offline (i.e. travel with a laptop) and it goes more than 3 days without an internet connection and you're still trying to use it. At that point you would need to hook up to a mobile phone or wifi and just run it once to gain another 3 days offline usage.
The data requirements to authenticate are really minimal too, it just involves your username and password being sent to the PreSonus servers, and them returning the renewed license.