What if I told you there’s an app which runs on all your devices, is free, has strong evidence-based support for its effectiveness, and allows you to acquire large amounts of knowledge and retain it indefinitely?

What if I told you it wasn’t even going to take any time out of your day?

There are two amazing tools which I use during those odd chunks of time. The first reads me articles I’ve saved, and requires only that I have headphones. The second is Anki, and it’s like having cheat-codes for knowledge.

Anki is a flash-card system that employs spaced repetition, which exploits our understanding of human memory to allow you to obtain a large amount of knowledge, and then retain that knowledge indefinitely.

We know from research that we remember things most efficiently when we’re tested infrequently over a longer time span. If you’ve ever crammed for an exam, you’ve probably discovered you’ve lost that knowledge a week or two later. Anki and spaced repetition gives us anti-cramming, letting you do a minimum of work to memorize information over a long period of time.

The working behind spaced repetition is simple. As long as you’re able to keep remembering, the time between successive tests gradually increases. New knowledge may be tested multiple times per week, but things you know really well will may come up every couple of years. The idea is to get you to recall knowledge just before you’re about to forget it.

Provided you practice regularly, it’s possible to learn and retain a tremendous amount of information. Regular practice sounds like it’s going to be hard, but I’ve discovered it’s actually the easiest part.

My day is full of odd bits of time that aren’t typically useful. Waiting for a tram, for my coffee to brew, standing in line at the airport. These chunks aren’t long enough to do much with, but they’re perfect for Anki cards. Each card takes only a few seconds, and if you reach your learning goals for the day there are always options to review ahead. Because you’re recycling time that would otherwise be wasted, using Anki comes with practically no opportunity costs whatsoever!

The Anki phone app comes with the ability to configure notifications if you have cards due. Switch that on. Simply having an icon on your toolbar provides a reminder you’ve got cards to complete, and can help act as a visual cue for whenever you open up your phone and wonder what you were meant to be doing.

Anki lets you make your own decks in the desktop client. I have decks for words I frequently misspell, dietary intolerances of my friends, people I’ve met, subjects I’ve learning, languages, and anything else that I know I’ll easily forget. However Anki also has a rich number of shared decks. For me personally, both cognitive biases and hiragana/katakana (Japanese characters) feature heavily in my learning schedule.

Anki has clients for Windows, Mac, Linux/BSD, iOS, and Android; as well as a mobile-friendly web interface. While the iOS client requires payment, the others are free and open source.

So what are you waiting for? Download Anki and start learning!