Originally Posted by
bikemig
It helps keep you in rhythm and it is somewhat psychologically self-defeating to have to walk. There are pay-offs to staying on the bike. Plus you have no idea what kind of shape the OP's knees are in. I know I baby mine a lot more than I used to when climbing.
Psychology? That's a big topic. Agreed, both ways. You want to go into a "contest" prepared to finish it and you want to have a plan for managing the difficult sections. I try not to punish myself for walking. I'm not a big walker, mind you, though I have walked with others and not been too disappointed. It is, as you suggest, very subjective.