Thanks for all of the interesting replies on this post.

I'm 63, still backpacking and still making homemade gear. I have several friends (men and women) in the 60-70 range who still hike with me. My 62 year old wife is still backpacking.

One thing I note, reading the replies, is that I have cut back more on my miles than many of you. I like to hike 4 hours or 8 miles (whichever comes first) per day. I rarely exceed this. When I return home I'm feeling good, not sore at all.

When home I usually spend 2-4 hours per day working around the house or at the gym. This amount of daily exercise seems to put me in good shape for the 4 hours of backpacking that I typically do per day.

One of my backpacking partners still prefers longer days of hiking. When we go together we usually camp at the 4 hour mark and then he goes on extra hikes around the camp area. That allows both of us to get what we want.