If you're looking into booking a flight with a long or overnight layover and carrying more than 1 bag, think twice ...
First off, you should know that even for international flights, United Airlines and ANA (All Nippon Airways) now only allow one free check-in luggage (I'm used to 2 free luggage on Singapore Air or Cathay Pacific). The second bag is $100. So on my last trip home to Indonesia, I flew United/ANA home for the first time, because the flight was $300 cheaper than Singapore Air's. This itinerary included an 18-hour overnight layover in Tokyo on the way there and a 10-hour layover (again in Tokyo) on return flight. Usually I'm a light packer and only travel with carry-on, but my trips home are different, with my family and so many relatives wanting me to bring this and that (shoes, Disney toys, Flamin' Hot Cheetos ...) and I always end up with a check-in luggage.
So. The long layover was attractive at first, allowing me to see a bit of Tokyo, but beware before you book a flight like this next time.
Apparently when your layover is more than 12 hours, they cannot check you in for your next leg, so I had to take my luggage out and put them in storage at the airport before going to Tokyo for the night. Fast forward to the next morning when I checked in for my next leg of the itinerary to Jakarta .... guess what? They said I need to pay the extra baggage fee AGAIN. Never mind that it was on the same itinerary and that I had already paid $100 in Los Angeles, because I was only checked in to Narita before, my $100 was only valid for LA-Narita. So now they've tacked on $200 already for the flight that was only $300 than Singapore Air! Not to mention the service sucked and the food was not as good. With a 11+ hour flight from LA to Narita they managed not to have time to give me the arrival forms on the plane, despite having asked for them.
I didn't end up paying in the end, but I had to spend 40 minutes explaining to the staff and manager that I understand that the second baggage is extra but that I had already paid in Los Angeles and should count for the entire itinerary, not just EACH LEG. I had to do the same thing for the third time when I checked in for my Jakarta-Surabaya leg. Even though I succeeded in talking to them, it wasn't worth the frustration and time. I don't know if talking to them would work next time, though, so before you book a flight with a long layover again, just keep in mind the extra costs of:
1) getting your baggage out and paying for overnight storage
2) paying extra baggage fee a SECOND time for your next leg - an entirely surprising and unreasonable cost.
In the end my overnight trip to Tokyo was quite expensive, although I had a great meal which was worth it, but I'd stick to Singapore Air next time ..