When we first started full-timing I was naive enough to think that when school was in session fewer RV'ers would be out, and we could forgoe reservations. At the time we had a one year membership at a nationwide, popular membership park system. They were the only one in the area of So Cal we were staying that was full. Our membership made no difference when we pulled in, in mid-January. What we found was that membership parks tend to be older parks that the group has purchased. Rarely are they as nice as the competition in the area. We let the membership lapse at the end of the term. Now we make reservations when heading into a popular area, regardless of the time of year.