It depends. I have heard from the graduate students at my school that the ones with wives work much harder and usually always finish on time. I imagine this i

It depends. I have heard from the graduate students at my school that the ones with wives work much harder and usually always finish on time. I imagine this is because they probably aren't allowed to spend more than 40 hours a week at school, else their wives would kill them. Near limitless time (which most graduate students think they have) can be a huge burden. I have no idea how this would translate for a startup, but a marriage can be a huge net gain fora PhD student.