A year of spaced repetition: what actually stuck
Last September I promised myself I would review flashcards every day for a year. I missed eleven days, which I am choosing to count as a success. Along the way I created about 2,300 cards, deleted roughly a third of them, and learned more about how I forget than about any single subject.
Short sessions beat ambitious ones
My first deck was enormous: every term from an introductory statistics course, imported in one evening. Within two weeks the daily queue was over two hundred cards and I started skipping days. What finally worked was a hard cap of twenty new cards per day and a rule that a session must fit into the time it takes to drink a cup of tea.
Writing cards is the real studying
The cards that survived share a few traits. Each one asks a single question. The answer is short enough to say out loud. And, most importantly, I wrote the question in my own words after closing the book.
If I cannot phrase the question without looking at the source, I do not understand the idea well enough to memorise it yet.
Copying definitions verbatim produced cards I could "recognise" but not recall. Rewriting them forced me to notice what I actually did not understand, which is where most of the learning happened.
Delete without guilt
A card that I fail five times in a row is almost always a badly written card, not a hard fact. I now either split it into two smaller questions or delete it. My retention went up after I deleted 700 cards, which still feels slightly absurd.
What I would tell myself a year ago
Start small, write every card yourself, review before breakfast, and treat the deck as a garden rather than an archive. The point was never the number of cards; it was the ten quiet minutes each morning when I actually thought about the material.