Each major program follows these two curves as it passes through the version parade. Bells and whistles (illustrated here by Happystar) increase exponentially. Usefulness for real work (here by Polistra) gradually increases then falls off. Both curves share the same inflection point. The peak of usefulness passes just as the maker's energy switches to bells and whistles.
For Windows, the useful peak was XP. For each of the major programs I use, I keep updating faithfully until I see that it's passed the peak; then I back off to the peak version and stop buying.
If I could be sure that the peak versions would always be available and supported, I'd pay big money.
The current icon shows Polistra using a Personal Equation Machine.