After 13 marathons my knees aren't able to sustain the wear of marathon training. I never used music while running. I felt it safer to hear anything approaching that wasn't immediately in sight. Things like dogs, cars, bikes, runners, preditors, anything that I should be aware of being present, I wanted to be aware of. Not trying to sound, sexist or parinoid, but women should be vigilant of their running habits, don't be so routine that someone can set their watch to your location while you run, and I feel it best to run with a partner.