$80-90k isn't actually that much less than a developer salary (in U.K., not U.S.), but it's an interesting question what I'd do if it didn't grow any more.
I'd probably put it into maintenance-mode, and start another micro-saas, as I love the freedom of working where/when/how I want. I'm hopeful of hitting $150k ARR by end of year though, and $250k next year.