...our practice of taking carry-on bags only, regardless of trip duration.

A little confused here. I recall vividly you describing how you would stage your luggage at hotels you would return to, while take smaller baggage for the side-trip(s). Sometimes return weeks later. Is the packing light new?

I've gone a bit the other way. I refuse to have lots of bags (learned that lesson!). But I'm starting to use a single medium check-in bag. People have become so obsessed with carry-on that overhead bin space can be problematic. Especially when someone sitting in row 25 decides they want to store their bag above row 18 where I'm sitting, so they can grab their bag on the way up the aisle (I presume). I actually volunteer to gate-check my bag whenever they request it. I have the few vitals in my camera bag (which I never check) that I might need in-flight. Gate check is free, which is nice, and I don't have to worry about bin space.

Last trip I didn't have any carry-on, just the medium check-in bag. This next trip I may have to because cold weather clothes are bulky, and carry-on may be needed just for extra volume. We'll see. I'm hoping not. If we both do a check-in, definitely no carry-on for me.

(Generally a medium check-in is as big as anyone needs. You'll hit the 50lb limit easily with it, so a larger bag is just a waste.)