Company Startup - What's the Exit Strategy?

I just finished up a great two-hour meeting with my financial advisor, who continued to reinforce the notion that, while I have no idea what I'm doing, I've got a great bunch of advisors and friends that can help me avoid the mistakes of my own ignorance.

I won't bore you with all of the advise, but one thing I thought warranted sharing with everyone is this:

"When starting a new company, always consider your exit strategy and your transition strategy."

OK, that's not exactly how Paul said it, but you get the point. In my case, I'm setting up a company with long-time friend, David Burmon. So how does this rule apply here? David is several years older and he started his family sooner than I - his kids are almost out of college, while my oldest is just interviewing for middle schools. From that you should assume he is:

a) Age-wise, closer to retirement than I
b) Financially better positioned to consider retirement

So the issues that need to be top of mind go something like this:

a) If David wants to leave the company, is there a mechanism to buy him out?
b) How do we evaluate the value of the company, if David wants to leave?

I'm off to the first meeting. I'll let you know how it goes.