Age is my biggest challenge. I used to be able to go 15-20 miles per day at 2 MPH. Now I find that 8-10 miles is good and 1 to 1.5 MPH is good. I still start up in the morning as soon as it is light enough to see but by 3:00 I am looking for a campsite. In some ways it is better than when I was younger. I guess that we mellow with age. In the past I thought that backtracking on the same trail was really bad. Now I just go until half of my trip time is used up and turn around. I remember reading that you should do all of your trips before you are 60 and I am 10 years beyond that and still going out.