I have a work uniform, of sorts. Half a dozen straight pencil skirts in shades of black, gray and navy, 10 of the same tank top and my fav 3/4 sleeve merino sweater in a dozen colors. Two pair of the same flats, in different colors. I wear that outfit 99 % of the time at work. I love it. It was my favorite outfit, so I gradually bought more of the same, to replaced what wore out or I didn't really like. I shop sales and eBay, since I know exactly what I need.
Now, im pregnant, so had to branch out a bit, but for the first 20 weeks or so, I just made do with my usual skirt and sweater in a size and then two bigger. I figured will need them again on the way back down, and can then have them altered to my usual size.