Not necessarily. It's well-known in the entrepreneurial community that most lawyers don't understand startups and will take an inappropriately heavy and expensive approach to these questions. Also, few embryonic startups can afford much in the way of legal fees. Hint: a good startup lawyer will typically agree to defer fees based on the level of funding the company's level of funding, i.e. you pay a certain amount at $100K, more at $250K, etc.

If I were the OP I would do as he/she has done and ask questions of other entrepreneurs first. For the record, I agree with aditya that vesting is the main technical answer here. Maybe you'll get lucky and grellas will chime in!