The older and more experienced I get, the lighter I pack. If I were heading out for a year long trip tomorrow, my standard carry-on and daypack is all I'd need.
For most people, the downfall - if you could call it that - is clothing. For some it's important for whatever reason to have a wide variety of outfits available. To each their own.
It's said that clothes make the man. Yeah, whatever... When traveling I'm satisfied with simple but comfortable travel clothes. I'm also willing to wear a pair of socks or pants for a couple of days.