it all depends what is he contributing.. You said that you believe "he can contribute a lot in many areas that need to be covered in order to build a succesful app company", but what is it exactly? Who's coding the app? You've already done first app, if he's contributing to marketing of the first app then he can get less than 30% of profits from that app. If you've already built second one, the same thing. If he's building the second app with you and brings more skill you might consider splitting evenly just for the second app, you don't have to give away equity within the company, you can make an agreement to split profits just for the second app, since he can decide to leave.