When it comes to the possibility of losing your luggage or having it delayed when travelling it is better to be safe than to be without clean clothes and the basic necessities of life.
Choose a light weight carry-on bag. First, pack any medications you would need in a 24-hour period. This is critical. I was once stuck on a runway in an airplane with a fellow passenger who was diabetic and did not have any of her oral meds. Not good. Be sure your cell phone or laptop are in your carry on bag as well. It is always good to pack a book in case of delays.
Second, pack one complete change of clothes. One of every item you might need: underwear, socks, shirt, pants, etc. Pack a toothbrush and tooth paste, a brush or comb, and travel size shampoo, conditioner, minimal makeup, deodorant and soap if you are picky about the brand names you use. Otherwise, don't pack them because those are simple items you can pick up wherever you land - no pun intended.
If you wear contacts, ALWAYS carry a back up pair of glasses with you and a contact container filled with solution. Do not pack the bottle of solution if you have other bottles of shampoo, etc., because you can only have three - three ounce bottles in your carry-on bag.
