For downloading day -to-day use and shorter shoots:
1. Pull card from camera.
2. Lock card (so the OS doesn't add crap hidden files to the card or affect the directory)
3. Insert into SD card reader
4. Copy the folders/files I need
5. Eject, unlock, and put back in the camera unless it is too close to full
When the card is full:
1. Put card in the bottom of the my stack of SD cards
2. Pull card from the top of the stack
3. Double check that all the folders have been downloaded
4. Put card in the camera and reformat
The second process ensures that I don't reformat a full card until some weeks or months after I've downloaded everything and the images have been backed up in multiple locations.
Note:
Understanding Life Expectancy of Flash Storage - National Instruments has the gory details in flash memory life span
a) Flash lasts tens of thousands of WRITE cycles -- unless you religiously take only one photo on the card before downloading and deleting it, the card will almost certainly outlast the shutter of the camera.
b) most cards have wear leveling technology that writes data to the least used blocks -- a card capable of storing 100 images should have a working life of maybe 1 to 10 million images
c) high storage temperatures are bad -- they cause the memory cells to leak charge and forget data