Honestly, when I saw that the Pfitz plan included 11 and 12 mile runs in the middle of the week, I was a little intimidated. Not only was I worried about finding time when it was light out to run for that long, I wasn't sure how I would handle it mentally or physically.
But now that I've done a couple of those mid-week 11-milers, I've come to LOVE them. It's nice to get a longer run in on a non-weekend day, and I can tell it's helping my endurance. Plus it's another opportunity to add to my ridiculously attractive running-shorts-and-socks tan, which is totally awesome for swimsuit season [sarcasm]