Ask HN: When to “move on” from an idea/business?

I've got a side project that is now a "business" which is profitable (~ $500 MRR). I'm sure I could increase the revenue anywhere from 2x to 10x with a couple months of work and experimenting.

I've got other ideas which I'm confident could bring in comparable revenue.

How do you decide when to go deeper with one idea versus start on something new?