The more I travel, the lighter my bag gets and the days of what if and maybe I’ll need are basically gone.  Now I can fit everything I need into a 50L Marmot Duffel for trips around a week, and have never had an issue using it as a carry-on. Longer trips or ones where I won’t have access to doing laundry I’ll use a Deuter 65L Travel Backpack that can easily be checked. I’m still a late packer, often doing it just hours before leaving and never using a list.  This leads to the first of my issues, and fortunately the one that brings me the least pain.