We often make a reservation for our first night out as anything North of our area can be very crowded at almost all times of the year. Because our itinerary is only a suggestion, we seldom make reservations.
When we were traveling with our DGKs during school breaks, we often had to make reservation and our itinerary was usually locked in if going to Natl. Parks in the West and Northwest.
We usually like to travel during the shoulder seasons, the weather is usually nicer, crowds are usually smaller and the wildlife is usually more active. Reservation are not as important in that case.
We don't think of ourselves as getting older, only that our girls are catching up with us in age. For some unexplainable reason, however, we don't like driving four to six hundred miles a day any longer and now that it takes less time to set up in camp, what with hydraulic levelers, usually only hooking up the electric and cable TV if available, we pick campgrounds that have very esthetic views and natural amenities that lure us into staying for several days instead of just overnight.
You just never know when you'll discover one of those places and often they are popular and without a reservation you may have to move a couple times in order to stay for a week and we do try to make reservation for those places.
We normally don't make reservations except for those special places that are very popular or if we are traveling during high season.