Monday & Wednesday: ~15 minutes. DH and our two sons have karate class from 6pm to 8:45pm. They don't like to eat a meal before that so we eat after. Since its late we usually do sandwiches (fried egg, tuna, ham & swiss, or grilled cheese or smoothies & muffins).
Tuesday & Thursday: ~30 minutes. It's a school/ work night, DD16 may or may not be at color guard practice. Meals typically include a main meat dish, a side vegetable and some form of bread.
Friday night: as little time in the kitchen as possible
This is typically our slow cooker night or something I prep ahead and toss in the oven then ignore til it's done. After a long week we want to relax & hang out.
Saturday & Sunday: an hour or so. DS11 loves to cook and these are the nights we really have time for him to indulge. He sees recipes he likes on Food Network (loves Bobby Flay & Pioneer Woman) or asks to make things I've done in the past.
We meal plan on Saturday evenings and I grocery shop on Sunday. After 7 years the kids are finally trained that I grocery shop once per week and if they don't tell me what they need/want when I ask, it's not going to end up in the cart and they'll have to wait a week to try again.
Forgot to add: We're in the U.S. Potatoes are a rarity on our menu. Much more likely are rice pilaf, grilled naan, or pasta.