I worked in international finance for a long time and got very used to international business and first class. At this point I have the money to travel in whatever class of service I want, but I still don’t shell out for domestic F most of the time. It’s just not worth it. My personal rule is to fly F if the flight is over 3 hours, and if I’m flying by myself (Mr. tm478 never wants to shell out for F regardless of circumstance!).