I was at Startup Day here in Seattle a few months back and Hillel Cooperman made the comment that if you’re thinking about starting a company and currently have a full time job, DON’T QUIT. That’s not to suggest that you shouldn’t start the company but why would you quit when you have an income from your day job and nights and weekends to work on your own project.
Starting a company in business school is pretty similar. It’s a great time to start something and very low risk, aside from the value of your time. In school you even have income, sort of, in the form of student loans.
There are obviously some concepts that require an all or nothing push from the start but most need a little time to get their bearings, working full time wouldn’t necessarily help accelerate that process. Besides, a startup is a labor of love and it’s easy to get myopic if you don’t have exposure to anything else.