I've just thought of another one.
Shop bought birthday cakes. My mum would always make the cake because paying someone else to do something you could do yourself was not only unaffordable, but also considered an excessive extravagance even if you had the money.
I think I, and many others my age (40s) are products of parents who experienced post-war rationing, whether first or second hand, and had the make-do-and-mend mentality. It still makes me hate to waste food or throw things away.
Now of course, things have come full circle again. Waste is avoided on environmental grounds, not always frugality. Recycling is woke, and often middle class.