I was an always make reservation guy but having just returned from a nine week trip out to the west coast I have changed my mind. Being locked into reservations for almost every night didn't allow any flexibility. We found places where we would have liked to stay a few more nights but could not break the schedule. On the flip side, if we did not have reservations on the Oregon Coast we would have been searching last minute. I now believe a combination of reservations at very popular locations and no reservation allow some flexibility and the security that we need on traveling trips.
Now if we are going to a destination and stay, like Henderson Beach State Park in Destin, FL, we will make reservations 11 months in advance. I will carefully pick our campsite for the stay.