Today I had a GREAT run, and I finished my 15 minutes run 2 minutes walk x2 no problem and raring to go. I stopped there, though, even though I could have gone on longer and I really wanted to try a higher intensity because it wasn't in my running schedule. I've been faced with this situation before, and unless I was not on a plan, I stopped to avoid burning out. On the other hand, I've also set out to run 2 1/2 minutes at a time and ended up running 25, just because I wanted to see how far I could go, and knowing I could do thta really helped me.
I'm curious about what other people do. Do you think that adding on more after you finish your session is a fine way to get more activity, or that you should just quit while you're ahead and have a fond memory of exercise for the next session?