We don't have a maximum # of cards setting in spaced repetition because it defeats the whole purpose of spaced repetition - if you're not reviewing cards at the proscribed intervals then you're liable to forget them. We are looking at adding an option for a set # of cards in a future release, but it would work by deliberately removing some cards from your review pool once you had too many so that SRS would be preserved.
I would very much like to have a fixed number of cards in SRS, and actually this has been discussed very often in this forum. There are many advantages
· you can choose the time you want to spend learning and repeating cards, e.g. "20-30 minutes a day" as
@daal wrote
· you can skip a day repeating if you have no time
· you do not feel the increasing pressure of due cards that must be reviewed as otherwise you are lost because the amount of due cards steadily increases
· you can review a small number of cards on days where you would not start reviewing because of the many cards in "real SRS"
The system I want to propose is a spaced repetition system, but the user can choose the number of cards each session. The number of categories is changing automatically, as categories are "deliberately removed from the review pool", and some of the cards in some categories temporarily do not belong to the review pool. I made a small Excel sheet to show what I mean.
There are 30 cards in the pool, some old and overdue cards and most of them new cards, all in one category. The scoring system is very simple: score=100 when the answer was wrong, score: +100 when the answer was correct until a top score of 1000. There is a daily amount of
10 cards to be reviewed.
The card selection first takes cards from overdue cards, sorted by how overdue they are. If there are more overdue cards than cards to be reviewed, only the chosen maximum number of cards is selected. In the example there are 8 cards overdue which are all selected. Then there are 22 new cards, from which 2 cards are randomly selected. So on day 1 the desired number of 10 cards is reviewed, and the SRS pool has 10 cards. There are 5 wrong and five correct answers assumed.
On day 2 there are 5 more randomly chosen cards, together with the 5 cards with a wrong answer on day 1 they again make up for 10 cards. The SRS pool increases to 15 cards. Now on each day more cards from the category are randomly chosen and added to the SRS pool, if the number of due cards in the existing SRS pool is lower than 10 cards, the chosen maximum. On day 4 there are enough due cards for review, on day 5 there are 12 due cards, e.g. more due cards than to be reviewed. In that case 2 cards have to be eliminated from review - not from the SRS pool - and in the example the due cards with the highest score of 400 were selected (card number 24 and 30). These 2 cards are selected the next day because these are the only overdue cards then.
Day 8 is a free day without review. That leads to 15 due cards on day 9, from which 5 cards are eliminated, again by highest score. On day 12 there are only 9 cards in the category which need a review. To reach the desired number of 10 cards the next category has to be added to the potential SRS pool (the categories from which cards are selected for the SRS pool).
That's all. If there is no natural order of categories, the user has to be asked which category should come next, or he can define some order for his categories. Categories are not only added to the potential SRS pool, but can also be automatically removed. That is the case when the desired amount of cards to be reviewed is already reached without the category. Categories are added and removed last in - first out, the last added category would be the first category to be removed.
Some more settings have to be made, e.g. when should a card be automatically be withdrawn from the SRS pool? In the example 100 days overdue (card number 23) will do - this card does not belong to the SRS pool at the beginning (in that case the score of 100 of the card leads to an immediate review too).
Maybe the system looks complicated, and maybe it is complicated for the programmer. But it is very very easy for the user: just the desired number of cards and the desired category to start with - nothing more to think about.
There are more advantages than just the easy manageable workload.
· you can start again reviewing cards after a break of 10, 20, 100 or more days without reviewing which is almost impossible with the current system in Pleco.
· You can review a list of 1000 or 3000 cards with a constant daily effort - the actual limit new cards option does not keep your daily work constant
So you have a maximum # of cards setting within a spaced repetition system.