We cook on weeknights. No kids though. My sisters with their kids have a tougher go of it.

Cooking itself doesn't necessarily have to take that long. We find it's the prep and the clean-up that's occasionally a pain in the rear. Anything that can shorten the prep or create less dishes to wash helps a lot.

As others have mentioned, we also try to make extra or do extra prep and use it for other meals. We freeze extra spaghetti sauce, pre-wash a bunch extra lettuce, make extra grilled chicken that can be quickly microwaved for a chicken caesar, have pizza dough in the freezer, etc. Peppers that we used for salads one night are used for fajitas or soup the next. We still "cheat" and occasionally use frozen packaged stuff like veggies and stuff.

It also helps if you have ingredients relatively on hand. We bought a vacuum sealer a few months back and it prevents food (particularly our cheeses) from going bad longer and stops freezer burn. We just buy packs of chicken breasts, wings, steaks, etc from Costco and defrost them the night before and away we go.