In my teens and twenties, I was never tired. I went for days on end with barely 4 or 5 hours of sleep, reading everything I could find, studying everything around me, talking endlessly with all the other people I met.
In my thirties and forties, I was sometimes tired, but I still motored on. As long as I remembered to watch what I ate and drank, I still had lots of energy, which was good, because as kids came along there was so much more to do.
In my fifties, I find that I am often tired, and simply willing myself to go at the same pace doesn't seem to work anymore. Luckily, though, I am still quite healthy, and I'm able to do things efficiently. I've learned to get my work done very effectively, leaving a fair amount of time for the other things in my life, but I still end each week with a longer to-do list than I started with. I can't play soccer three times a week like I used to, nor do I seem to bounce up and down the stairs like I did, but those are only minor disappointments.
I know that this progression will continue. The important thing is to continue to learn to get the mandatory things done as quickly and effectively as possible, to leave as much time as I can for the things that matter (like losing to my granddaughter in Finca, Acquire, or SmallWorlds).
Our 95-year-old neighbor doesn't remember our names anymore, but she still has a beautiful smile and a kind word. We don't get to control everything in our lives, but I'm surely grateful for all the blessings I've received.