Oh, I will be STUDYING this thread!! I have been mostly low/low for a long time although, I flirted occasionally with being more low/high. It is a struggle, for me. I need variety and change, and I know that's not always a good thing.-- it leads to waay too many clothes in my closet.
For me, jeans are my daily uniform, so I spend more, these days, on them, than on anything else (remember, I'm gloriously retired and serve as a volunteer). I don't have a "perfect" pair, yet, in straight or skinny cut, but I love NYDJ for their boot cuts! I'll also spend more on some workout clothes, especially tech fabrics when I'm running regularly. I spend on undergarments, too, mainly because I love something lacy or slinky, next to my skin. Lately I am also moving up with jewelry choices. I find that heavier, more substantial pieces look better now, and often they are more costly.
Other than that I am largely low/low because since nothing I do keeps bugs entirely at bay. Oh, I tried cashmere and I do love it, but unfolding a sweater to find a hole eaten in the center front convinced me that good-quality synthetics are just fine for me. When I lived in a suburban development, I didn't have this issue, but with a lot of land around our house, here, the good stuff seems to just draw them out.