I've been doing it since March, wearing the same dress. It's wool jersey, I made the dress and lined it with Bemberg to protect the fashion fabric. I wear it for everything except mopping the floors, Pilates, and swimming. LOL. I'm changing on June 21 to a different color, will wear each dress for one season.
I sew from a sloper, it's a basic sheath dress. (same style as a "little black dress," a very simple sleeveless sheath). They are flexible for different activities (can shop in them, go for walks, go to the theater and museums, whatever). You can vary the look with scarves or jewelry but I mostly wear it plain. If you do this, jazz up your dress with stuff you already own, the point is not to go out and buy a bunch of stuff to look different, it's to be comfortable just wearing the same thing and not spending money. The current dress is light blue so it's a little more difficult to keep clean, unlike a darker color. I just picked up some green linen to make the one I'll start wearing on June 21, it's kind of a deep grass green color ("Juniper"), very pretty, probably easier to keep clean than baby blue but still a summery color and will also work in the evenings. I have my eye on rust linen for fall and then my black one for winter.
It's not that hard, I hand wash it every 1-2 days and launder it on delicate in the washer once a week and air dry it overnight. I wear dresses way more than pants, though, and I could get used to capsuling even further, like instead of 15 outer garments, maybe 8-10 or less. :o
My four-season "challenge" of one dress per season ends on March 21, 2018, maybe then I'll wear 3x for the next year, or 2x. Or maybe just take the plunge and wear one dress for the year.
If you do it, find something you look great in, something comfortable, easy to wash and dry on a regular near-daily basis. You won't get bored if you know you look good in it and it's a fabric that can take the rigors of daily wear. Natural fabrics if possible, so they can breathe. Polyester is going to wear out faster with washing, etc.