One of the things Andrew does very well is build his system around his own physiology and style. What he wears and carries is very much dependent on his plans for the trip. This includes not only the expected conditions, but how he will spend his time.
Ex. On our WT3 trip, Andrew was much more used to a style of wake up, break camp, go all day, turn in versus the more leisurely group style we fell in to. We spent some quality time hanging out in camp in the mornings and evenings. As a result, Andrew would hang out in his bag/quilt until we had breakfast ready. It's not that he wasn't prepared for the trip, he definitely was, it just wasn't his usual style and he had to make some adjustments on the fly. I came in to the trip as one of the few with a group background, so I was set for hanging out in camp. If anything, I was over prepared for sleeping, and wound up carrying some insulation I never used. Andrew, on the other hand, slept just right as far as I can recall. You likely won't see him on here asking what item is best for what situation either. He's either tested it, and knows what works best for him, or he's out there testing it. He also doesn't eagerly jump to the newest gear just because it's new. I'm pretty sure he's still using a GoLite parka from several generations back.