When starting my freelance career back in 2012 I had a pretty simple idea on how to track time using only google calendar and this tiny web app I wrote. Used it literally every workday since then, and even got a colleague (another freelancer) to use it with the quote “the first time tracker to ever work for me, and I’ve tried a lot!”. He is still using it last time I checked.
So I guess it is actually used by one more person than me!
I'm generally eager to share what I make, and have written quite a few open source tools. It's gratifying to polish up a piece of software to a high standard ...
But deliberately not sharing your creation, keeping things idiosyncratic and a bit chaotic also has it's charm :) The bliss of knowing that you don't have to worry about code quality or users asking for new features!
I wrote some simple tools, e.g. a note-taking app, and scripts to organize photo's. I also wrote a time tracker :) but I open sourced that one (it's called timetagger).
So I guess it is actually used by one more person than me!