Commercial software often charges a fee to update after a period of time, or is offered strictly on a subscription basis. Videopad has that option as well.
VP frequent updates are more cosmetic than indispensable. New features, UI refinements and quick glitch fixes that may not be encountered by most users.
As mentioned, the latest unlicensed release can be installed, to explore what's new. This seems a fairly liberal policy.
Retain your installer and registration info.