First, here are the clothes I packed for a week at the beach: not really a ton of stuff, but not hyper-minimalist either. Normally, I would have rolled these up to go in my bag. While this can be a good use of space, it has a few problems: first, it is hard to keep them nicely rolled/folded in the bottom of a bag. When you get where you are going, you have to dig around for what you need, and things inevitably come undone, and I end up with basically a pile of laundry in my bag.
Here are the clothes folded and placed in a packing cube. Note: it is not actually cube-shaped; more of a rectangular prism, really. (I didn't come up with the name.) They are soft-sided nylon, with mesh panels on top, and a double-zipper on three sides. The more you put in them, the better, because things slide around less and they hold their shape.
Here are all the clothes packed into the cubes. These are made by ebags, and I ordered my set of small, medium, and large off Amazon when they were on sale.
The thing I really like is that they make my bag so neat. For my valise bag, they are especially useful because I turn them on their sides and file them. They have handles, which makes pulling out the one you need even easier.
For the beach trip, I packed everything in a large duffel bag. When we got to the condo, I took out the cubes, unzipped them, flipped the top under, and placed them directly into the drawers in my room. Unpacking: done.
I am thinking that these have several further applications: keeping gym clothes organized, separating diaper bag essentials, etc. We shall see!