Digital cameras usually do not come with big built-in memory of their own. Hence in order to use the camera practically, it is required to have adequate Secure Digital card, or SD Card.
Choosing the best SD card also depends on your anticipated usage. For instance a 2 GB card should be able to hold about 750 images, videos recordings up to 20 minutes and mp3 or other music files up to 35 hours see this table for details. If you are habitual of taking RAW images or like to take videos often, then 8GB card should serve your purpose
However you cannot just purchase any card, checklist to help you buying most suitable card is given below.
Knowing appropriate storage size is essential, considering your current and future needs. Usually cards give 2GB worth storage. You can also opt for SDHC, i.e. High Capacity Card, capable of providing till 32GB space. Latest available in markets are SDXC cards, these Extended Capacity beauties can hold maximum 2Terabytes, though cameras compatible to it are rare. Mostly you need to purchase new one to enjoy SDXC
Generally SD cards are compatible with cameras. However it is still necessary to check if card you are choosing works properly with your camera. Compatibility can be checked from the product detailed manual or internet.
Card speed is very important as it determines how rapidly your camera is ready to take next picture. Cards of varying speeds ranging 2-10 MB are available in market .Generally 6X card is more than enough for normal use. It is better to check high speed cards in your camera, as it may have some compatibility issues.
Strike One, You are Out
Having one high capacity card although sounds more feasible, but what if that card is stolen or misplaced. You will lose all precious memories and important files. So keeping many cards of relatively smaller size diminishes risk of losing all.