Another difference between me and 16x. :-)
For me, a day with a short easy run is better rest than a day off completely. I never take days off intentionally (well, maybe a couple after a marathon), but find that life schedules one for me every now and then (most recently, I took last Monday off - too busy - after 9-10 weeks with no days off, for example).
Mind you, I'm not 47 yet....