We do one or two ~one week trips every year. We try to take a "big" trip every couple years.
They used to be very carefully planned, but our philosophy on that has changed completely.
We had vacationed in Hawaii where we got extremely busy before the vacation and didn't plan it as well as we usually do. We stayed at a gorgeous resort on Waikiki Beach, but drove all the way around Oahu at least a couple times. We hopped a plane to do a long day trip to the big island and to hike Volcano Nat'l Park, visited Diamond Head, spent a whole day exploring Pearl Harbor, had surfing lessons on the North Shore, took a biplane ride out over the sacred falls, etc.
We liked that experience so much that we took a trip to San Francisco early last year where all we had lined up was a rental car and the hotel for the first night. Then we'd decide what we wanted to do for the next couple days and head that way. We got to experience a couple of neighborhoods in San Fran, Alcatraz, Napa, Sonoma, Lake Tahoe, Reno, Monterey, Big Sur, etc. We had an amazing time!
That trip was such a great success, that we made our big trip last year a three-week trip to southern Europe with almost zero planning. Again, we had a hotel room for the first night or two and a rental car lined up. We also had tickets to the Italian Gran Prix and a hotel room during that event because everything around Monza books solid that weekend. We spent a couple days in the Lake Como area, then drove to Switzerland for a day, down through France to Monaco for a couple days, over to Nice, down to Florence and Rome, across to Rimini (on the Adriatic), a few days in Venice, etc. And we had stops in rural areas throughout where we got to feel like we were really experiencing the cultures we were visiting.
It was the trip of a lifetime, and we plan to do something similar every other year. For us, stripping away the pressures and expectations that come with having plans makes the vacation much more of a real vacation. I used to go on vacation and after a few days I just wanted to be home "sleeping in my own bed." Now, even after three weeks I am sad to see it coming to an end.