scheduler: Reduce Interval growth for very mature cards

Use this at your own risk. If this add-on has a bug all future scheduling might be ruined. I use it for me. Hardly anyone else uses it. Maybe it's useful for you, too. Before you use it you could have a look at the source code which is only about 20 lines. If you have set a maximum interval in your deck settings this add-on will sometimes give you strange intervals, for details see here! Feedback, Improvements, Error reports are welcome - open an issue in my github repo. # My motivation I hate forgetting/rescheduling cards with very long intervals. It feels like I wasted reviews (even if I don't use a lapse interval of 0%). This add-on reduces the next interval for very mature cards which should slightly increase their retention rate. Lowering the intervals overall (with a reduced interval modifier) is not an option because this would lead to a lot of additional work, check the calculations in the manual here. Having an add-on that slighly lowers the interval for very mature cards is soothing. I'm not sure if such a reduction is really useful apart from this psychological effect: Unless you limit your Anki use to languages you have the problem that most of the knowledge you learn now won't be relevant for you in the long run: Either it will be dated or your needs have changed. So forgetting very mature cards shouldn't be a problem in many cases. Maybe the additional workload could be justified like this: If each review lasts 10 seconds and ... - if the next review interval will be 500 days then the "time investment needed to remember the card contents per day" is 10/500 = 0,02 seconds/day (for the next 500 days). - if the next review interval is 20 days then the "time investment needed to remember the card contents per day" is 10/20 = 0,5 seconds/day (for the next 20 days). # Implementation This add-on overwrites one method from the scheduler(`_nextRevIvl`). To compare the built-in scheduler with my modifications I use my add-on deck and card info sidebar during review and in it enable the option "try_to_show_origvmod_scheduler”. Keep in mind that after Anki calculates and shows the new intervals for easy/good/hard it applies some randomness (fuzz). So if you look into the info of the prior card you should always see a slightly different number.