I’m going to quote myself from another thread on reddit:
Reschedule-on-change adds an entry to the review log of every active card in your collection. See also: Deck Options - Anki Manual .
[All of those revlogs need to be synced with your collection …]
Sure, the increase in server traffic is a good thing to consider. But your major concern should be that if you run that a lot, your collection might get so big you can’t sync it anymore at all. Are there limits on file sizes on AnkiWeb? - Anki FAQs
As an example – my average reps-per-day is about 80, which adds 80 revlog entries. But I have about 8000 active cards and reschedule-on-change adds a revlog entry to every active card, so that’s 8000 revlog entries. Running reschedule-on-change would add the equivalent of 100 days of review history to my database each time. It’s like a rapid-aging disease for your collection.
See also: Using FSRS Helper to reschedule cards .
The other drawbacks are –
- In order to use reschedule-on-change, you have to save a change in your FSRS Options. FSRS Helper rescheduling can be done independently.
- If you want to undo reschedule-on-change, it will also undo anything else you changed in the same Save in Options. FSRS Helper rescheduling can be undone on its own.
- Reschedule-on-change can only be done at the level of the Options preset. FSRS Helper rescheduling can be done on your collection, specific decks, or even specific cards you select in Browse.
There is an open proposal to update the built-in reschedule-on-change to behave more like FSRS Helper rescheduling: Improve "Reschedule cards on change" .