For me, it's usually until the work starts or until the end of the project. A lot of the people in the biz are there to make lots of money with as little work a

For me, it's usually until the work starts or until the end of the project. A lot of the people in the biz are there to make lots of money with as little work as possible. The cracks show as soon as they're expected to half the work. Hackathons have been a good, cheap way to filter a cofounder, with a time limit. You see whether the tech guy is willing to build, the product guy is willing to think outside the box, and the business guy is willing to take the time to research the market and put effort into explaining the product correctly.