Right now we're playing a 3.0 Scarred Lands game on Saturday afternoons and a 2nd Edition Vampire game on Thursday nights, and we've been really good about sticking to that schedule. Occasionally we have to miss a session because someone is travelling for work, or because someone's relatives are visiting from out of town, but that's usually just once or twice every two months.
But then, it's not too difficult for us; only one person in the group is still in grad school (the rest of us work for a living, as we like to remind her), and none of the married couples in the group have kids, so making time twice a week to hang out and play a game isn't too much of a stretch at all. If someone needs to permanently reschedule a game (changing jobs or whatever), generally we can settle on a different night and time.
It's much better than we ever managed in college, when for some reason we were lucky to find time to play once every two months.
--
and that only if we were lucky
ryan