My paternal grandmother never varied her weekend menu. Ever. Not for forty years, that I know of.
Friday supper- Fish, usually fried. If one if us gave her a pack of venison, she might substitute fried deer steak.
Saturday supper- grilled hamburgers. Mawmaw don't cook on Saturday night, so it's grilled burgers on paper plates.
Sunday dinner - Chicken. Fried, barbecue, baked, gumbo...Varied, but it was going to be chicken. Sunday supper was leftovers, because nobody cooks on Sunday nights.