I'd say my experience is the same. Not only as far as frequency, but in terms of percentage of total mileage - I'm never not tired at the end of a run that's more than around 30% of my weekly mileage - and I never get the feeling of active recovery, when I'm fresher after the run than before, unless I've gone less than 15%. That's true for me no matter what my weekly mileage might be at any particular time.

Got it done yesterday - and had kind of a funny experience. Three or four miles into my warm-up I passed a guy doing a run-walk, and after we both stopped for water at a little park, we chatted for a little bit before I re-passed him. I usually run later in the day than most of the local marathoners, so while I'll see them at shorter local races, I don't often see them on the road. This guy, turns out, is an ultra-runner, just a couple of weeks off a trail 50K, out for a shake-out run. We chatted for a little and I went on. Then about five miles later, not long after I'd started my race pace segment, we passed each other in opposite directions on a boardwalk. Six or seven miles after that, we rounded the same corner in different directions. It cracked us both up.