Something annoying about learning: the things that make learning feel productive are usually the things that slow it down. Cramming feels great. You sit down, you grind through the material, and by the end of the session, you feel like you’ve got it. And then two weeks later - gone. 1[■]
The fix is one of the most well-supported findings in learning science: spaced repetition. Instead of bunching all your practice together in one session, you spread it out over time. In the 1880s, Hermann Ebbinghaus discovered what is now called the forgetting curve. Without any review, you lose most of what you learn within a day.
2[■] Your brain is doing exactly what it’s supposed to do - filtering. You encounter an enormous amount of information every day, and your brain has to decide what matters and what doesn’t. If you only see something once and never come back to it, your brain reasonably concludes it’s not that important. 3[■] When you encounter the same material again, your brain essentially says, “Oh, this keeps coming back. Must be important.” And it invests more resources in holding onto it. Each time you successfully recall something after a gap, you reset the forgetting curve.
So how long should you wait between sessions? The optimal gap is roughly 10-20% of the time you want to remember the material. For instance, you can space your practice 3-5 days apart if you are studying for a test in a month. 4[■] You’re not trying to prevent forgetting; you’re trying to practice retrieving after some forgetting has occurred. As long as you get it right, the exact intervals are less critical.
You don’t need to overcomplicate this. Start with something simple and build from there. 5[■] It’s that you’re willing to do the thing that feels harder in the moment because you understand it produces better results in the long run. That’s true for spacing. Honestly, it’s true for most of learning.