I've been struggling with poor sleep for months. The 3am wake ups (can't fall back asleep) are really bad.

I figured it couldn't be coffee because I fall asleep easily. But it turns out that lingering caffeine can let you fall asleep at bedtime and then come back to haunt you later when you move into lighter sleep.

I've been in denial about my caffeine consumption because I've gotten away with it until now.

I vibe coded a little caffeine metabolism tool to face reality. I wanted something with a simple half-life formula and drag and drop using common beverages.

What becomes clear very quickly is: my caffeine consumption needs to be way lower and earlier to fix my sleep issues.

the half-life thing is what gets most people. they stop at 2pm thinking they are safe but its 5-6 hours. had a coworker who quit coffee at noon and still could not sleep, did not connect it until we traced back