OK I just thought of something else... Maybe someone already brought this up but, there have been so many variations of these questions....
Let's say I pay for SPlat lifetime, then buy an add-on at an extra price. Is the add-on then also lifetime, or do I need to keep paying for new versions of the add-on? Or can the add-ons be subscription? Ideally I would like a subscription where I can add (and maybe remove) individual add-ons as needed.
[Edit] Ok I just realized berlymahn asked almost the same question.