I started C25K (the first time) on my own, then OH joined in and stopped. I prefer running on my own as you get time to clear your head and enjoy the fresh air but I do have a companion, I run with my Labrador who is handy at pulling me up big hills and keeps me motivated to the end, he even carries my water bottle when we are finished - plus it tires him out, always a bonus!! Who do you run with and why? I'm intrigued (or nosy!!).