Regarding the wrinkle-free claim for Wool and Prince, I found this to be true only up to a point. I took the company's advice at face value and would just throw the shirt into my backpack and go; after a while the wrinkles became pretty much permanent. No amount of dry cleaning fixed them. One should also watch out for stains as the shirts stain very easily. I was unable to wash out a grease stain. The coloration also faded over the 3 months I wore the shirt without washing.
Wool stills seems to be the best candidate for long use, little washing. I currently own only wool t-shirts (3 of them) and they are holding up well. They are 100 weight, so two of them have developed small holes around the belt area (which are only visible if one looks very closely and stretches the fabric). They were bought in May and it is now November. In general, based on previous purchases, the life of these wool clothes is around 100-200 days of use.
Jeans are also pretty amazing when it comes to how often they need to be washed. I find that they also last about 200 days of wear and only need to be washed 4-5 times during that time.
The odor-free claims are actually rather accurate if you allow the clothes to air out. My experiment with not showering or changing clothes at all for two weeks (even when sleeping) led to a very ahem distinctive smell developing; it may be better to switch between outfits daily and allow the other outfit to air out during the day. I have yet to try this and stay consistent.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.