This is a question of curiosity.
Let's say you've launched a product, we can call it ProductX and after a few months you have a number of users, engagement and for the most part it's pretty stable. At what point do you say "Okay, I think it's time to start working on another product idea from my list while I maintain ProductX?".
Personally, I have a long list of ideas and a number of them are ideas that I feel passionate about. But after launching 1 product or project and getting to the point where I'm maintaining it I start to want to start something new again while I maintain the current product. When is it too soon to start working on a new idea after a launch?