When exactly did this happen?

So this is what has happened to me. I've been running so frequently and for such large amounts of time, that what is considered a long or challenging run to most people (or even to myself before this summer) is now just an 'easy' run or off-day in my mind. It used to be that, mentally, I'd consider anything longer than ~2hrs a long run. During marathon training, I'd probably do one long run per week. If any of the runs were >=16 to 18 miles, they were spaced out by at least 7 days to properly recover, both mentally and physically.

My training schedule for last week was:
'Easy' on Tuesday and Thursday. 10 repeats up and down Market Street and 10 on North Adams street (two of the steeper, longer hills in the flat city of Wilmington. After the repeats, head into the YMCA for 45 minutes on the treadmill at 11-15% incline.
'Hard' on Wednesday and Friday. 3 hrs on the trails at FairHill. A 2.5 mile warm-up and cool-down sandwiched around 4 repeats of the steepest sections of the park.

What?!
The 'hard' workouts were 18 miles and well into what qualifies as a hard run. But the 'easy' runs of hill repeats and treadmill inclines totalled 13.0 miles and almost 2hrs. When did I suddenly start thinking that qualified as easy? I have no idea when it happened, but it feels great. Seeing what I've been able to push my body to do, what I've been able to shape it into both with respect to appearance and performance has been incredibly satisfying (and incredibly tiring as well!).

Last week was also supposed to be the first time that I strung together 5 challenging runs. But, I was exhausted by Saturday. My legs had nothing left and I stopped my run just 80 minutes in. 5 days was asking a bit too much.

This week is off to a tough start, too. Last night at FH I increased my trail workout from 4 loops to 5 loops. This brought the total workout to 21.5 miles and 3:23:30 for the time. My run ended at 7:45pm. My goal this morning was to accomplish my 'easy' workout...12 repeats on Market and Adams streets followed by 60 minutes on a 15% treadmill incline. But, with my run starting at 4:40am, that gave my body less than 9 hours to recover and get ready. In the past, I'd normally wait a full week before attempting another challenging run. I'm in immensely better shape right now, but not in shape enough to reduce that time to 9 hours. I could have slogged through the workout, but that would have had significant repercussions for my workouts later this week (and possibly longer if I got hurt).

With today being an 'off' day, I'll return to the schedule tomorrow: Repeat Monday's workout tomorrow morning; Thursday morning attempt today's scheduled workout; off Friday; running on the Appalachain Trail in Western Maryland on Saturday and Sunday.