German psychologist Hermann Ebbinghaus measured in 1885 that without reinforcement, your brain discards roughly half of new information within 30 minutes, and up to 80% within 24 hours.
For your SPL theory exam, forgetting is not just inconvenient - it is dangerous. You need knowledge that stays with you in the cockpit, not just until the test.
Spaced repetition works by showing you a card just before you would forget it. Each time you successfully recall something, the next review is pushed further into the future. Each successful recall also strengthens the memory trace, making it harder to lose.
The result: you spend less time reviewing things you already know well, and more time on the things that actually need attention.
In 1987, Polish researcher Piotr Wozniak created SuperMemo, the first program to automate this process. His algorithm, SM-2, became the foundation for nearly every modern flashcard app - including Glidr.
Every card has a personal interval (days until it appears again) and an easiness factor (how quickly that interval grows). Your ratings update both values, so the schedule adapts to you.
After each card, you rate how well you recalled the answer:
Be honest. Rating "Easy" when you hesitated tells the algorithm to wait longer than it should - and you will have forgotten it by the time it returns.
A card rated "Good" might be scheduled for:
After three or four successful reviews, you may not see a card for months - because it no longer needs reinforcement. That is the algorithm doing exactly what it was designed to do.
Study mode uses spaced repetition. Cards appear according to the SM-2 schedule - only cards due today, in the order that helps you most. This builds deep, lasting knowledge. Do not skip days if you can avoid it.
Cram mode ignores the schedule entirely. It is useful the night before your exam as a final confidence check, or when previewing a new topic. It does not update intervals, so your long-term schedule is unaffected.
Start early. Begin 6-8 weeks before your exam to give the algorithm room to space intervals properly.
Do your due cards every day. A consistent 10-minute session every morning is far more effective than a 2-hour marathon once a week.
Aim for 20-30 new cards per day. Introducing too many creates an overwhelming backlog within a week.
Use the ratings honestly. There is no score - no one sees your ratings. Admit when you struggled.
Trust the schedule. If a card is not due, reviewing early does not help and disrupts the spacing that makes the system work.
Good luck, and good soaring.
Based on the SM-2 algorithm by Dr. Piotr Wozniak (1987) - [supermemo.com](https://supermemo.com)
