Oh! so. I gave up on the capsule wardrobe thing, generally, but! but! I travel for long-term a lot an usually I pack down quite small (one month on a kids’ school backpack). This is how I do my mixing styles thing for a long-term smaller travel wardrobe:
my base pieces mix with most styles. These are usually my most expensive pieces and are usually acquired extremely lightly used through a in-person thrift store (lol), poshmark/ebay or through an outlet sale/store. For me, these are merino wool (because of low stink factor/long life) and are generally black/gray/teal (my base colors for my wardrobe). These are things like leggings, turtlenecks, tanks, cap sleeve shirts. These I will wear over and over and over again.
To have more mixed wardrobes I focus on the cheaper/lighter pieces that change the outfit. These are:
These are more likely to be made of not-amazing fabric but have the fun personality. For example I have a hot pink school girl skirt and 1940s pencil skirt. The same base layers can be combined for totally different aesthetics by changing the skirts and earrings.
I get all of these off poshmark/mercari/ebay by acquiring fast fashion second hand and living with that. some of my fun pieces I do sew.
The things that I spend big dollars for are statement shoes and long-lasting shoes. I have 7 pairs of shoes and they all pretty much fulfill a specific function - one of those functions is that I wear my silver platform boots with wings when I need to punk rock an outfit.
I stay within the same colorways EXCEPT for a few accent pieces. My whole wardrobe conforms to those colorways.
I do investment pieces as well that usually tend to be dresses, and I stick with black/white that can then be dressed up. If they’re suits, I go wild with colors and use whatever underneath as the neutral pallette.
For example, I have a lace A-line dress that I’ve worn in a 1950s style fit and then have also worn with a crinoline + hot pink bondage harness. Both are an aesthetic.
My biggest advice I give to people into fashion is not to think that capsule wardrobe means only the seasonless, beautiful fancy blob pieces. You’ll most regret not having your amazing fringe-glitter jacket (or whatever it is) than you’ll regret not having 3 different white $200 tanks. Just make sure that all the base pieces can be mixed or matched.
ETA: I currently have 238 pieces of clothing. Average price of each piece is $15 - that’s because I have most of it free from clothing swaps/freepiles/made myself but then I also own an $800 custom suit.
ETA2: My article on my wardrobe spreadsheet https://www.racked.com/2018/4/10/17215194/closet-clothing-wardrobe-charts-data
ETA3: I am very small compared to the American market. This means I usually either get US vintage clothing which fits my proportions better usually, I alter the clothing I do get OR I get stuff made on an asian sizing scale which generally fits me better. I have accepted alteration as part of the cost of doing business.