Assuming you are technical, even a failure is probably a net positive to your career prospects. This is particularly true if you are very early in your career,

Assuming you are technical, even a failure is probably a net positive to your career prospects. This is particularly true if you are very early in your career, or are later in your career and have been involved with some well-known or successful companies along the way so far. I view entrepreneurial experience as a positive that tends to correlate with intrinsic motivation, follow-through, and analytical risk-taking. Obviously YMMV, and a lot depends on how you execute. If you have a crappy idea and throw years of your life away with no demonstrable progress, obviously it's not going to be easy to tell a story about. But a failure reasonably well done will be a good learning experience -- and obviously even a modest success has lots of upside. The biggest real issue is opportunity cost, factoring in not just income but the potential to be part of something epically successful and all the experiences, halo effects, and relationships that come from that.