I've read that also. Sure doesn't happen around here. I'm always making a new recipe and wouldn't
repeat a favorite that often, not a main dish, anyway. The one thing that has stayed constant in this house is steaks on the grill, usually with a twice-baked potato of some kind, sauteed mushrooms and a green salad. The only thing that varies is the potato preparation.
This started early on in our marriage and has gone on for close to 45 years. DH loves steak. It used to be once a week, but not quite so often now. So that's my biggest rut but such an easy meal and usually on the weekend. Also love grilled hamburgers, but we don't eat them but every couple of months or so.
Favorites come and go, but there are a few things I've made for years and still make, but not even once a month, let alone every 9 days. Some that come to mind are Spinach souffle, found a good recipe and always use it.
A chicken, green pepper, mushroom and cashew stirfry from an old Betty Crocker international cookbook that certainly isn't authentic, but oh so tasty and also a flank steak and pepper stirfry from the old Time-Life books.
We used to have spaghetti and meatballs often and I've not made that in more than a year. Oh dear, now I'll be fixated on it.
For years, if I started thinking outloud about what to have for dinner, dh and dd would shout out "steak, spaghetti, pork chops, hamburgers". Wishful thinking, I guess.
We also have tacos, with various fillings ever so often and enchiladas, but lots of different recipes.
And I almost forgot my answer to fast food...frozen cheese raviolis layered with good bottled marinara sauce and baked, served with a salad, green olives and garlic bread. It used to be almost a weekly thing for when I had really worked hard and was tired. Guess I don't work that hard anymore, we don't have it often.
That's a good question and I bet most people here don't repeat things that often.
Tonight, we're having tamales from the refrigerated case at Costco, Mexican rice, pinto beans, salsa, and guac. I hope those tamales are good. I've never made them from scratch.