A. Taking several memory cards on a trip is a good idea. If one gets lost or breaks, you still have more.
I usually recommend buying several smaller cards rather than one big one just for this reason. Of course, no matter the size, you want to get a card with the right speed.
A card that's too slow will leave you waiting for files to transfer. Your camera might take seconds to take the next shot. You could miss a golden photo op while waiting for it to catch up.
You might decide to buy the fastest card, but you could be overspending. Plus, it might not even work with your gear. Fortunately, I can tell you what to look for.
First, you need to know what kind of card you're using. The most common type is the Secure Digital card.
When buying an SD card, you'll have a few choices to make before you even consider the speed.