When is goal-dependent. If you want your Kickstarter to make $100k, you can look at conversion rates across similar products and then estimate from there. Will you need 1 million people on social media? 1,000 on an email list? And so on.
That said, I don’t think the best networkers go about it that way. Providing value for free is their default setting, they’re just smart about building a community around it, so whenever the time comes, they know what goals they can rally their community with to accomplish together.
Not all relationships should convert. That’s just normal. I don’t think that’s a reason to cut ties. If you provide a baseline of value that’s out there in the world for everyone to use and access, people can always default to that. Will you email them 1-on-1 if they never buy from you? Probably not as much.
Let the strongest relationships emerge naturally and don’t worry about the rest. That’s how I think about it.