I'm happy, and somewhat embarrassed, to admit that I already adhere to the once a month rule. Jeans are at their peak comfort after at least five wears. They are actually pretty uncomfortable after a fresh wash imo. That said, I've never washed any of my clothes because I was concerned with bacteria, usually it has more to do with some mustard stain, or a bit of funk emanating from the armpits or "nether-regions." But a dirty pair of jeans is a comfortable pair of jeans.
My jeans are a bit different because they have a bit of spandex stretch in them. I try to wash all my clothes when they are dirty/smelly rather than after I wear them once. Jeans I can wear 4-5 times before they get too stretched out. Usually they aren't dirty, they just aren't fitting as well as they usually do.
Hang on though, this doesn't say whether or not he also wore underwear. Most people do wear underwear and wearing underwear takes the same amount of energy and water to wash as a pair of jeans, right? Actually, I'm just assuming that because I don't know much about the consumption of resources for washing machines. Anyway, I would be interested to know how this would play out for people who don't wear underwear and the percentages of resources consumed. Edit: Also, this site talks about the student that did the "experiment" and also Levi's "freeze your jeans" thing and ends with a quote from Junkscience: "So remember: clean clothes aren't green."