This concept didn't come to me easily, as obvious as it seems. It's hard to get past the idea that your week isn't divided in parts anymore: the work part, and the much shorter weekend part. Every day is the same now: wide open. My new mantra is "Any day, any time."
We were working out a plan to get together with friends, and it suddenly dawned on me. The calendar is wide open now, still divisible, but in a different way. Just save Saturday and Sunday for friends who haven't retired, and the weekdays for those who have. It opens up the entire week to see friends, an extremely free feeling!