Samsung 64gb and 32gb non-micro cards. Now that Samsung only makes micro cards, Sandisk 64 and 32gb cards. Have some older, slower Lexer 16gb cards. Never had one go bad, but I copy to laptop's internal HDD, AND an external HDD. Only after I have two copies do I reformat card in camera.

I use a card reader to copy the SD card to the HDD's. This allows me to use TeraCopy (free on windows) to do the copy as it verifies each file copied with a CRC check.

I've heard that it's better to use full size SD cards rather than micro cards in your camera. Opinions?

I did limited research on the reliability of SD cards and I was surprised at the numbers. Most distributors claim the MTBF of >3,000,000 hours. What that means is that on average there will be one failure every 3,000,000 hours. That probably explains why I've never had an SD card failure. I've always wondered about the obsession of having two cards in a camera for backup when in reality, the SD card is the most reliable component in the chain of possible camera failures. It is my firm belief that the principal cause of SD failure is mishandling. The contacts are exposed and it's very easy to grab the SD card by its contacts. This may result in static electricity being introduced to the card. Static electricity is the number one killer of electronic components. Furthermore, there are a limited number of actual chip manufacturers. Samsung is one of those and until recently, Micron in Idaho. Micron has gotten out of the chip business. The various names seen on SD cards are resellers that buy their chips from the chip manufacturer then have them packaged with their name on the SD card. Resellers such as SanDisk and others are not in the chip manufacturing business. They only package chips and it's not likely they actually do this themselves. They most likely go to a packaging house that packages for other resellers as well. I hope that I have not confused the UHH community.