About a month ago I purchased a pair of Nike Zoom Skylons as a possible replacement to the 825. I find them decidedly uncomfortable. There must be a post in the forefoot that makes contact with a pressure point on the balls of my feet because I get periodic numbness. There is nothing to the tongue so you notice every minute difference in the way I lace them. The tread is noticeably worn after less than 150 miles. Needless to say they will not make a repeat appearance in my rotation. However, as I got ready to run this AM, I thought I'd give the 825s one last go 'round. Just putting them on, I know it's a better shoe for me. 7 miles this morning and no numbness, no discomfort. I think they still have some life left in them. So I guess it's 800 miles and counting.