Do I need to reformat the memory card for my new camera that was in a different brand?

Old camera was a canon a470 the new camera is a nikon s2550. Also would you take a spaare battery even if its a brand new camera abroad?

Actually you should reformat your card every time you download. Always reformat your card and you will have few, if any problems with it. It takes a second to do it. Always, always, have a spare battery. You are dead in the water without a battery.

I take my battery charger with me if I'm going to be gone over 24 hours.

At the end of each shooting day, you need to copy all your images to your computer and once safely there, format the card using the cameras format feature. Do this every time you successfully copy your images to your computer. If you do not have your notebook with you, take three or four 4 gb cards with you. SDHC cards are really inexpensive now, so buying some extras will not hurt you pocketbook much. A 4 gb card costs from £2.10 to £4.30 on Amazon UK depending upon the brand and Class card you buy