Welcome Emma,
I'm pretty new to quilting but started sewing as a kid. I'm slightly younger than your next youngest sibling and from well north of you, but I was raised with many of the same values you were (buy if you need it and can afford it or do without) but never heard about washing my feet if that's all I could wash. Wonder if it has to do with going barefoot--which wasn't common for us. Too cold most of the year, I guess. My mom said always to wear clean, non-holey underwear in case we got into an accident, though.
Ginny in snowy Duluth, Minnesota