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The Spacing Effect:
Why spreading beats cramming

The same total study time produces dramatically different results depending on how you distribute it.

What is the Spacing Effect?

The spacing effect is the finding that information is better retained when study sessions are spaced apartrather than massed together (cramming).

First documented by Hermann Ebbinghaus in 1885, it's one of the most reliable findings in learning science. Over 100 years of research confirms: spacing works.

The counterintuitive part? Spaced practice often feels less effective in the moment. You forget more between sessions. But that forgetting and relearning is precisely what builds durable memory.

Spaced vs. Massed Practice

Same total time, very different outcomes

Cramming
Spacing
Time per session
Long (hours)
Short (minutes)
Sessions
1-2 before exam
Many across weeks
Immediate performance
Good
Moderate
Long-term retention
Poor
Excellent
Feels like
Productive
Slow

Optimal Spacing Intervals

How to space based on your retention goals

Remember for 1 week

First review: 1-2 days

Subsequent: Increase by 1.5-2x

Remember for 1 month

First review: 1 week

Subsequent: Then 2 weeks, 1 month

Remember for 6 months

First review: 2-3 weeks

Subsequent: Then 6 weeks, 3 months

Remember for 1 year+

First review: 1 month

Subsequent: Then 3 months, 6 months

How Cruxly Implements Spacing

Calculating optimal spacing intervals manually is tedious. You'd need to track every piece of information and schedule reviews accordingly. Nobody does this by hand.

Cruxly's algorithm handles spacing automatically. It tracks your performance on each question, calculates optimal review times, and surfaces the right material at the right moment.

You just open the app and study what it tells you to. The spacing is built in.

FAQ

Why does spacing work?

Spacing forces your brain to reconstruct the memory each time, which strengthens it. Massed practice keeps information in short-term memory without building durable long-term traces.

How much time between study sessions?

It depends on how long you need to remember. For a test next week, space reviews 1-2 days apart. For long-term retention, space them weeks or months apart.

Doesn't cramming work for exams?

Cramming can produce decent immediate performance, but information fades rapidly. If you only need to remember for 24 hours, cramming 'works.' For lasting learning, it doesn't.

How do I stay motivated with spaced practice?

Spaced practice doesn't feel as productive as cramming—but that's exactly why it works. Trust the process. Short, regular sessions add up to much more than marathon study sessions.

Space your learning automatically

Cruxly schedules optimal review intervals for you.

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