Thanks, but I'm not sure that 8gb is large enough for me. Although more cards is spreading the risk of a card failure, changing cards on a shoot is also introducing a risk. I'd also rather not be having to keep checking the storage during a shoot. Having more cards, would actually increase the risk of card failure, although that failure would be likely to affect a lower number of files - which is what I suspect that you meant.
I wondered if it's possible to use a USB cable to transfer images to the computer, instead of removing the cards & using a card reader?
I use USB cable to transfer images from card to computer, as I do not have a fast card reader.
Though I use a 32GB card, I rarely fill it up with more than 600-700 shots, even though it can hold about 1600+ RAW images from D3300. The reason is simple, with more than 500 RAW images, the directory listing over USB takes quite some time. As I have never shot more than 300 images in a day, or over 600 images over a trip, for me an 8GB or at the most 16GB would suffice.
Regarding failure, I would rather have a card fail with 200 images than have one fail with 1000. The reason for having a number of smaller capacity cards is to minimize damage in case of card failure (though it is rare with Sandisk cards, it happens and that too at most inappropriate times). That is why if I am shooting in conditions where I cannot afford to loose any image, I would go for a body with two similar card slots and write the same image to both the cards. Cards are cehap, travel and opportunity lost is not.