There's also a non-binary approach -- exercise some of your options (i.e. not 0%, not 100%). Figure out how much money (e.g. $100, $1000, $2500, $10000?) you're comfortable losing entirely should the stock become worthless, and what percentage of your vested options that allows you to exercise, and use that as a starting figure. Then adjust that based on how much more risk you are willing to take because you really think the company will succeed.
