Well, I freaked out today. After 118 shots on my D7100, it flipped to the second card and started with 0001. The first card is 32 gb and it was empty when I left the house. I know I get 1100 shots on my 4 gb card so I was panicking about what could have happened to card 1. After uploading my pics, I discovered the last number on card 1 was 9999. Whew!