Funny that 18 megapixels is not listed . . . but by looking at the numbers for 16 and 22 megapixels and a 16GB card, you can estimate that you'll have room for more than 2000 pictures per card.
I typically put a new card in my camera every couple of days, even when the current card is less than half full. I don't travel with a laptop or other backup tool, so this provides some protection against total loss in case a card is damaged or defective.
Ann,last year when we were on this tour I had an SD card fail. The slider which protects your pictures bound up with some of my best shots on it. I was able to fix and download to my mini laptop I take to back my pictures up but it never worked again. If I were you I would take a couple extra SD cards as things can happen and the cost is next to nothing any more. This is a trip of a life time and you don't want to try and save a few dollars when you pay so much to get there.
I never put more than 2 days shooting on a card so I won't lose those important shots.
Gary
Reading cantraveller's reply, and thinking about what was said, I definitely agree. I usually (but not all of the time) take my laptop with me when I travel and upload photos every day, but I keep the sd cards intact until I do a full backup at home. When I bought my current camera (Canon 60D), I wanted to get the largest capacity sd cards available. The professional at the photo shop I go to strongly advised against that (even though the sale would have been much higher). His logic (and it makes perfect sense) was to buy a number of cards, so if one failed my loss wouldn't be all of my pictures. My largest are 16GB cards.
Comments
http://kb.sandisk.com/app/answers/detail/a_id/69/~/number-of-pictures-that-can-be-stored-on-a-memory-device
Ann, Yes, most chargers for laptops, ipads, phones, cameras are 110-240 and don't require a converter, just an adapter.
I never put more than 2 days shooting on a card so I won't lose those important shots.
Gary