Luggage: Pack only what you can lug.
The best decision I made for this trip: Travelpro luggage. The thought “Worth its weight in gold” kept coming to mind. Both pieces are carry-ons and while the smaller of the two does not fit under the aisle seat, it does fit under window seats. A friendly and helpful flight attendant (sometimes an oxymoron) led me to a Business Class overhead bin for storage during the flight to London.
Researching, reading and comparing reviews led me to purchase new luggage even though I have used sturdy 2-wheeled bags in the past. The older luggage is heavy even before packing.
Ahhh! The right suitcase is like a good-fitting pair of shoes. Baby Bear porridge, Just right.