Maybe hard to believe for a golf forum, but at age 51 yesterday was the first time I've walked 18 holes (started golfing at 27 so I missed the teen years where that probably would have happened). My preference is to walk 9 with push cart (most of my rounds) and ride if I'm playing 18 (maybe 2-3 times a year tops).
Yesterday was a nice typical Chicago summer day, 90°, sunny and humid. Used an umbrella with my ClicGear to try and shade from the sun a bit.
Shot 91 for the 18. Had a blow-up 9 on one hole, a couple of 7s, and started tiring after about 12 holes but rallied to finish par-birdie on 17 and 18 (pars 3/5), so that was good.
I don't think I'll ever do that again willingly though. Was really hurting on the drive home and the rest of the evening. A little better today with the help of ibuprofen and Bengay (I guess that's how it's spelled now).