I am flying Thai Bkk/Tokyo then ANA to SFO then UA to Las Vegas. They all have different baggage rules. The Ticket was given to me and the person got it with his UA FF miles.

My question is whose rules apply and the return is UA to LAX and THAI to bangkok. Just don't want to be stuck for a big bill for excess luggage.

Oh sorry Carry on and check in I need to know about
Thanks so much