Many commentators encourage making reservations a couple of days in advance and being flexible. Help me resolve that with the stories of 000,000s of people using the trail a year; with most places along the way having only a few single rooms (health reasons, I need a plug at night); with places saying they do not take reservations. (I'll choose The Zuriaín Stop Hostel, for an example.) How do I reconcile high use with limited sleeping places?