Memory cards for smartphones come in SD, miniSD and microSD formats. Few things have changed more dramatically over the last few decades than computer memory. The tiny smartphone in your pocket has way more memory than the computers on the Apollo 11 spacecraft had when astronauts landed on the moon. But with these changes have come different standards, speeds and headaches.

Today there are three types of memory card media available for smartphones: SD, miniSD and microSD. Almost every device is moving toward support for microSD cards, and our suggestion is to only purchase microSD memory cards. Many packages come with miniSD and SD adapters, so you can quickly turn your microSD into one of the other formats if necessary.

Different phones support different size memory cards, and there is no good general rule about how much memory to purchase. Almost any smartphone will work with a 1-gigabyte memory card today. Before you purchase a larger card, make sure your smartphone will support it. If your smartphone has SDHC support, it can usually work with much larger cards – but not always! Check the specifications of your smartphone before making a purchase.

We have been buying only 4-gigabyte memory cards for our smartphones recently, an they usually cost about $20 each. Amazon is a good place to look. With 4 gigs, we can fit all U.S. street maps for TomTom and about 1,000 NOAA full-size charts, representing the entire East and Gulf coasts. That will leave us plenty of space for photos and short videos. We also have a spare memory card available for times when we want to shoot longer videos.