3 pairs of shoes. No matter how long.
One pair of “sandals”. One pair of sneakers. One pair of dress shoes.
I’m leaving today for the beach for 3 days. I have beach shoes (waldies - croc’s ripoffs) for the beach. Running shoes for running. Dress shoes because we’re going out to eat one night.
I am packing to go away for a long weekend and must check luggage for the very reason this thread was started. Four nights, five days 9 outfits. If I really try to adapt, I can get away with four pairs for 9 outfits but that is still not a carry on amount. I spend two hours packing, repacking and trying to double up last night until I gave up and repacked in a bigger bag with my normal size liquids. 
That’s pretty much how I pack. One pair of comfortable heels that can be dressed up or down, one pair of flip-flops, and running shoes for running/working out. I usually wear either the heels or the running shoes on the plane to save room. (I actually find heels the most comfortable on the plane 'cause they have plenty of room for swelling feet and keep your feet exercised.)
Hey, me too! Except 8 outfits.
One pair of shorts, 5 shirts, 3 t-shirts, and some underwear. One pair of sandals, and the dress shoes I’m currently wearing. They come off at 5:30, and won’t go back on until Wednesday.