What Is Spaced Repetition? Seeing a Word Again Just Before You Forget It, Not Reviewing on a Fixed Timetable
Spaced repetition is a way of timing review. Instead of running the same words past you on a fixed timetable — today, tomorrow, the day after — it brings each word back at the moment you are about to lose it. Answer correctly and it comes back later; answer wrong and it comes back sooner. It does not teach you how to remember. It decides when you see a word again, which is also why neither "learn it and walk away" nor "drill it ten times today" tends to stick.
Two boundaries up front. Spaced repetition does not guarantee that you will remember a word, and it does not predict an exam score. All it does is bring a word back just as it is slipping; the part that actually fixes it in place has to be done by you, and it requires you to keep coming back.
1. The definition, in one sentence: just before you forget it
Hand the question of when to review to a rule instead of to your instincts: leave a word alone while it is still fresh, and call it back at the point where it is about to slip away. That is the whole idea. Everything else is how that one sentence turns into something you do each day.
Spaced repetition does not teach you anything. It decides when you are asked again.
So it is almost the opposite of "review more often." Reviewing more often is what you do when nothing is scheduled; a schedule exists precisely so that most possible reviews get skipped. Reviewing a word you would still have remembered costs you a session and adds little, and reviewing it long after you have forgotten means restarting from closer to zero. The method's only claim is that the timing of a review matters, not just the number of them.
2. Why "learn it and walk away" does not stick
Leave something unpractised after studying it and the retrievable part drops fast at first, then more slowly — that is the forgetting curve. The steepest loss happens in the first few days, which is exactly the window that "learn it and walk away" skips past. What spaced repetition does is place each reunion at the moment the word is about to slip, rather than after it has already gone.
Testing yourself straight after learning only confirms that you remember. Testing yourself later, when you are about to forget, is what actually moves things forward.
3. How one word gradually becomes secure
- Recall it and it comes back later. Every successful retrieval pushes it further out; that is how the gaps widen.
- Fail to recall it and it comes back sooner. That is not a reset and not a punishment, just an earlier reunion.
- Leave it too long and it costs more. Come back after many days away and the word is usually unfamiliar again, and progress you had banked slips back noticeably.
- Translation, Dictation and Speaking each keep their own timing. Knowing it in translation does not mean you know it in dictation, so practising one format leaves the other two permanently fragile — see One Word, Three Due Dates.
4. Three things you can do now
- Work through the batch VocaX lines up for you. Open the app and finish what is scheduled for today; you do not need to pick which words to review, because that is already decided. For how much to take on each day, see How Many Words a Day.
- Hand the words you could not recall to Flags. Flag a word when you miss it and it gets collected in one place, so you can go over that set together later — see Turning Mistakes Into a Signal.
- Do not drill the same word twice in one day. Getting it right right after seeing the answer is recognition, not recall, and it does almost nothing to make the word stick. Leave it today; it will come back on its own — see Should You Redo a Word Right Away.
5. What VocaX does here
Exactly one thing: it decides when you meet each word next. You just open the app each day and finish the batch it has lined up. Words you got right move out, words you got wrong move in, and none of that requires your attention or your understanding of how it works. Your only job is to come back on time — the rest carries on by itself.
6. Where it stops helping
- It does not guarantee you will remember. We will not tell you how much you will retain after how long. We do not have that number, and we are not going to invent one.
- It does not predict exam results. It schedules when you see a word again; it does not estimate a score.
- It does not choose your words. The schedule only re-asks words you have already started; what to learn next is your call or your wordbook's — see Choosing a Word List.
- It only works if you keep coming back. However good the timing is, a word will not stick without you showing up.
- It is an iPhone app. VocaX is iOS only; there is no Android version.
What the app can do is bring a word back just as you are about to lose it. The part that actually makes it stick has to be done by you.
FAQ
Is spaced repetition just reviewing more often?
No — almost the opposite. A schedule exists so that most possible reviews get skipped. Reviewing a word you would still have remembered costs a session and adds little; reviewing it long after you forgot means restarting from closer to zero. The method's only claim is that the timing of a review matters, not just the number of them.
How much review is enough each day?
Finishing the batch VocaX has lined up for that day is enough; you do not need to add more. VocaX's daily goal defaults to 50 and can be changed on the progress ring on the card screen. If you do want a different volume, finish the reviews before adding new words — see Review First or New Words First.
Should I redo a word immediately after getting it wrong?
No. Getting it right straight after seeing the answer is recognition, not recall, and it does almost nothing for retention. Flag the word and let the app reschedule it; it will come back sooner on its own.
Can I use it to cram before an exam?
Not really. The value of spaced repetition is that it places each reunion at the moment you are about to forget, and that runs on a rhythm of days and weeks. The night before an exam calls for something else, and this is not a substitute for it.
I have not opened the app for days. Do I have to start over?
No. Come back after a gap and some of the progress you had banked will have slipped — that is normal. Just work through the review that piled up; there is nothing to reset. VocaX will not nag you about it either — see Why We Do Not Nag You.
Axiom One LLC — VocaX. Figures current as of 15 September 2026.