I only carry on. I have a wheeled carry on size suitcase and I carry a laptop backpack which holds my laptop, camera, phones, books, sundries, etc. The carry on suitcase goes overhead and the backpack goes under the seat in front of me.

I have my liquids in 3oz containers and pack them in a ziploc. Everything is available in that size - bug spray, sunblock, shampoo, conditioner, lotions, toothpaste, etc. Not a problem. And if i need more of anything i can obviously buy it there.

If I run out of clean clothes i either get them washed by hotel staff or do it myself by hand.

Last trips have been 2+ weeks and I still brought home stuff i didn't use or wear.

Not waiting for luggage is AWESOME.