Interesting thought! How many years would be reasonable in your opinion? Like 2 years or so?
I have one app that does that annually, but calls it a "pay once for 12 months of upgrades" instead of an "annual plan"... which is basically what it is 😂
I don't think I see an appreciable difference (in terms of iterating/improving) between the best of each that I use, but I def evaluate subs at renewal to see if I got value from them in the past year.