I used to live on the road for about six months of the year, my wife and I have traveled all over. We usually limit ourselves to 1 carry-on, possibly a gear bag for snorkeling.
The main trick is to pack things that can be swapped so you can keep fresh outfits without carrying tremendous amounts. Plan to do 'sink laundry' every few days to keep your 'delicates' fresh. Bring a little Woolite in a squeeze bottle or buy the packets in a travel store.
If you forget something, buy it!