Here’s my (short) story. I’m a single founder in mid development, and this is a side hustle. I expect to deliver by the end of this quarter, working in my spare time. The product is solving a problem that I have. I am footing everything, and am not even entertaining the idea of bringing anyone else (cofounder or otherwise) on board until the product is complete and works the way that I want it to. Then once it’s marketed and gets traction, then and only then would I look for help.
But that’s just me and that’s the point: do what’s best for you.