So I just came back from a shoot, put my SD card in my card reader and copied the files from the card to my computer. At least I tried to, but after the first image Windows reported an error message that the connected media was not formatted in a recognisable file system.
The photo recovery software is running now and it looks like I've gotten lucky this time. Now I'm wondering if I should toss that SD card or if it's a good idea to try to format it and continue using it. I.e. is it likely there is something physically broken, or is it probably just a random error in the file system that can be fixed by formatting the card? It was a pretty expensive Sandisc Extreme 64GB card, so I don't feel like just tossing it (I bought it through Amazon, not sure if any kind of warranty applies …)