What have you built for yourself?
Recently, I've started to learn a new language, got myself a Duolingo, everything went really well. However once levels got harder, I kept forgetting correct sentence structure/words. And Duo's exercises didn't help me on that front too much. Thus I've spent some time and built myself a language learning app focused on repetition. I can add cards from duo or manually, those cards can be used via voice (TTS) and with various masking and hints. Really can notice difference in learning now and combining it with Duo.
On the same note, I think last year Splitwise (app for tracking finance use, split expenses) introduced more payment tiers and greatly limit access for a free usage. Therefore I've built a finance planning app with some little dashboards and entry points for my household. Using till this day. Every day!
Some notable mentions: - Shopping list app, to simply track what we need to buy; - Very minimal Flash card app to learn language as well (more than a decade ago)
I know all of those apps are all already developed and available to use, but I can't explain the feeling having it built yourself and having sure that no-one sees your data but you. Also, having app small, straight to the point, ads-free helps greatly too!
Very curious - what have you built for yourself that you're proud (or not) till this day?