Ok so if you're looking to use equity to build your team but already have a product, brand, some traction what's the best way to give away equity to co-founders? Obviously you can't just say here's X% of the stock - what if they leave next week for a new job, dont do any work on the site for the next 6 months? Presumably there are ways of structuring this but what are they and are they expensive in legal terms?