Ask HN: I have a small project generating 1700e annually, should I keep going?

I started this small project for booking tennis courts in 2018. It was free until this year, when I started charging clubs for using my platform. Out of 15 clubs, 14 clubs agreed to pay for my solution. I'm doing some updated, no marketing at all. It's a side project.

Should I sell it? Work on it? Leave it?