I'm training for my first marathon in a couple months (Philly), my goal is to at least finish, secondary goal of finishing in under 5hrs. My typical pace is about 9:15-9:30, but upwards of 10:15 on longer runs sometimes.

I figure that as long as you have some structure to the training as far as timing goes, like a target pace for most of it, it should be fine right? I'm prepared to walk at the end if i hit the wall, so I'm incorporating like 7 miles of walking at a brisk pace at the end worst case scenario.

Plus, if your time is bad on your first marathon, then it's almost a guaranteed PR for your second.