I actually don't find that clothing is that important in my packing decisions anymore, no matter what the length of the trip, so am surprised that so many travel packing lists/articles tend to focus on this. I travel for long periods at a time (1-2 months at a go, usually, for 5-6 months a year), and have no problem going with relatively little clothing that I wear for multiple days and wash along the way by hand. Layering is of course key, especially when a trip spans dramatic climate differences. All in all, clothing decisions have become pretty standardized, but even there I'm sure I'm sure I could even take less than I currently do.
But no matter where or how long I travel, clothing just doesn't constitute the biggest element in my packing these days. In fact, increasingly the biggest driver of luggage weight and space for very long trips seem to be (a) toiletries/medicines and (b) electronics-related gear. For (a), I tend to bring everything I "might" need (first aid, antibiotics, etc.), as well as consumables like contact solution that I'll definitely need because it is very hard and/ or expensive to get easily abroad, especially in developing countries, and hunting such things down is *not* how I want to spend my time. The good news is that I 'use up' many f those heavy liquids as I go, thereby reducing luggage weight over the weeks. As for (b), if I carry an SLR camera, two smartphones (my US phone and my 'travel' unlocked phone for local SIM cards); a small convertible laptop/tablet; travel chargers and converters; etc. etc. -- that's easily 15+ pounds right there! So between these two packing categories alone the weight very easily takes up much of the 50 lb. airplane max. Other non-clothing items also tend to be heavy depending on the trip, including everything from clothes washing powder to a headlamp flashlight to a Swiss army knife to extra batteries, etc. etc. etc.
As for carrying it all - I am a female who just turned 60 but still use a (good quality) backpack, IMHO infinitely more practical and ergonomically better designed for carrying around a 40-50 pound weight than a roller or a duffel. This is especially true if you have to walk over uneven surfaces, long staircases, etc. -- including in train and bus stations or anywhere else you need to get. The other advantage of a backpack is that you have your hands free to carry other smaller items or hold on to handrails or whatever.
Anyway, I am lucky in that I don't have back or joint problems at this point, and I realize I may not be able to do the backpack approach for many more years
, but I've never found an alternative that is more practical for travel when you yourself are responsible for moving your crap from point A to B, so will definitely hold on as long as I can! (Or until I move completely to a traveling style that includes **other** people responsible for my heavy luggage -- and that day will come!!!!
).
