i'd working with your Software for years. Most paid by the contractors, clients or employers - some of them until now, so renewed licensing each year again.
At the moment I'm helping in a monastery, that lives only from there donations and gifts of visited pilgrimages.
Here we cant used a license, where we have to pay for any year again and again. Sure, there we can (and still do so) use older versions.
But I would like to recommend that you maybe thinking about a kind of "perpetual license". Which may even like to be a little more expensive, but just include the newer versions for 5 or 10 years or longer periods like that - maybe "lifetime".
Likewise, I would hope that there also should be a licensing programs for schools, universities, charities or charitable purposes, with some lower pricing, they can handle.
Not that I would not appreciate your work! Quite the contrary!
I could also imagine that those school or charities users would be the best places to promote the proper use of AIDA and thus normal customers are more likely to pay attention to a purchase a normal license.
I hope you can understand what I mean and had to say "Sorry for my lousy English"! But I have to recommend that for years and now I used the chance for ;-)
Furthermore: GOOD LUCK and all the best from Germany,
yours ... Frederic Ch. Reuter
Ps.: Here in Germany we have a charity platform for those sort of founders, named "stifter-helfen.de" and witch means "donors help". They proofed your legal donor state based on German law and after that, those special users can buy some software on there stock for less, then a couple of euros - each time for 2 Years. There I got Windows and Anti virus software for the monastery as told your above.