Caffeine Half-Life: Why Your Cutoff Is a Guess
Ten men, the same caffeine dose, half-lives from 2.7 to 9.9 hours. Why the 6-hour cutoff rule oversells timing, and what the dose data actually shows.
Sleep & Energy · 18 min
Evidence-based self-improvement
Small, doable upgrades for habits, focus, money and confidence. Every article names the mechanism, cites the study and year, and ends with one action you can take today.
Featured · Money & Growth
The Psychology of Money Habits: Why Saving Feels So Hard
Americans save just 3.0% of income, and willpower isn't the fix. The psychology of money habits, plus the proven system that grew saving from 3.5% to 13.6%.
Read the guideLatest mechanismsAll series →
If-Then Plans: The Famous Number Just Got Cut in Half
The if-then plan works. But a 2025 meta-analysis of 642 tests puts it at d = .36, not the famous .65. Here's how to write one that still earns its keep.
Habits & Starting · 19 min
The 25-Minute Myth: Your Pomodoro Timer Isn't Science
Breaks reliably lift your mood and cut fatigue, but a meta-analysis of 2,335 people found no significant gain in performance. Here's what 25 minutes really is.
Attention & Dopamine · 17 min
Sad Spending: Retail Therapy Works, Just Not by Buying
A hypothetical $100 cart cut lingering sadness by more than half in 2014. Sad spending explained, the 300% myth debunked, and why choosing beats buying.
Money & Growth · 18 min
The Snooze Button Myth: It Costs 6 Minutes, Not Your REM
A sleep lab wired up 31 habitual snoozers: three snoozes cost about 6 minutes of sleep, not your REM. The real lever isn't the button, it's your bedtime.
Sleep & Energy · 17 min
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