Last year, as I was going down the South Kaibab Trail, I met Maverick going up. He had done more than 40 rim-to-rims so far that year. I don't recall him having a large pack.
He said his wife works at one of the rim stores, and she doesn't mind his being on the trail as much as he is. I do wonder, though, how it's possible not to be bored when one does the same route dozens of times a year.
It's probably fair to say, though, that, if you showed Maverick a photo of any ten-foot stretch of trail, he could tell you just where it was along the North or South Kaibab Trails.