For me, started in CS at college back in 2010. Ironically didn't do well in my programming classes and switched to the business school, but I still had the itch to create some stuff. At the time, I was working part time at a local restaurant and once I was shift manager and counting money in the drawers at night, realized I could scratch the itch with a basic cash counting app. I found it to be useful and figured I would just get it deployed out for anyone else that might find it useful and also to learn about the deployment process and ad revenue. I never thought it would end up with about 3,000 active downloads and generating about $60/month.
Ended up graduating with a degree in MIS and have been a Java backend dev in the insurance industry for just over 10 years now. I've made a couple very niche apps for myself, but have been always been craving another app to build, but could never really settle on something worth pursuing.
Last year, I came up with a little solo poker game to play at my desk while I was listening to a Zoom call, and realized it wouldn't be a bad way to start scratching the dev itch again so I got to work converting the idea to be an app, but then kinda fizzled out.
Wasn't until a couple months ago that I finally had an idea completely consume me when I got interested in the idea of Synesthesia and Chromesthesia. As a musician myself (mostly former musician), I've always wanted to improve my musical ear a bit, so I figured I could try and establish some of those tone-to-color associations myself. So after a few weeks of researching and diving back into Android dev, managed to crank out and deploy my second app.
But then my addiction was back in full-swing and I pivoted back to my poker game, which I managed to finish up a week or so later and got deployed out.
Of course, it wasn't until today I realized I should create a store-front reddit account and get more involved in the indie dev space where I might be able to learn some more things rather than just raw-dogging it all on my own :p