I was actually thinking of Pre today. The fact that he ran 10 miles about every morning at 6 pace was huge. Just rambling, but I run with a decent amount of people my age and they do quite well on 40-50 a week. I actually understand
the balanced workouts and rest. It does make sense for older runners. However,
I have a tough time settling in my mind the 80-90% effectiveness one reaches is good enough. You have to decide if the 25+ miles more a week is worth it. That's my struggle, but I'm mixing things up a bit to find a way to do it and stay fresher.
Which goes back to Pre. Get some morning runs in and find a way to use the evenings effectively.