Trac was my first app to go all the way: idea, build, App Store review, Play Store review, real strangers using it and emailing me about it. It was a tracker for anything — you defined what to count and how, and it gave you charts, themes, backups to Google Drive, the lot. The engineering was the smallest part of the education. The rest was everything around it: store review processes, crash reports from devices I'd never heard of, the strange intimacy of a one-star review at midnight, in-app purchases and the accounting that follows them. I retired it when the honest answer to 'why does this exist?' became 'because I haven't turned it off yet.' The tracking-app market filled with well-funded products, and keeping pace as one person with a day job stopped being craft and started being guilt. Shutting down something that works is its own lesson, and a senior one: knowing when a thing is finished, and letting it be finished, is a skill I've since had to use on much bigger systems than Trac.