Digital nomads: how do you keep track of visa days across countries?

Curious how other people handle this because it became a bigger headache for me the more I traveled.

I used to rely on passport stamps, calendar dates, Notes and a lot of mental math to keep track of how long I could stay somewhere. That worked until it didn’t. I misunderstood one of my visa stays and ended up paying thousands in overstay fines.

Schengen’s 90/180 rule, visa extensions, tax residency thresholds and passport validity make it even messier when you’re moving between countries regularly.

That experience eventually led me to build Travl, but I’m curious what everyone else does today. Spreadsheet? Calendar? Another app? Just passport stamps and memory?

And what part of keeping track of your days abroad is the biggest pain?