Used to be like you, now I focus on creating high conversion landing pages if I'm trying to build a project for profit, and only build the full idea if I get enough sign ups.

Another thing I do more, which I find hard as a developer but somewhat more rewarding, is talking to potential users. Sometimes it makes you realise your ideas are crap haha.

But it's a different thing to build for fun, which I tend to do less these days and want to do more.

And agreed on the learning side. Building full-on projects is the best way to learn. I've picked up so many skills that have landed me new amazing jobs, i.e. that's basically how I transitioned from a native iOS developer to a full-stack React/React-Native developer.

Keep building! and don't forget the user side :)