Cards can take more than 100 000 writes on average. Basicly it means that memorycard is immortal, considering that cards will get obsolete in few years when memory technology goes fast forward, todays 32 gigabytes memorycard is useless in 5 to 10 years. I have many different kind of memorycards in my drawer, sizes between 16 MB and up, now they are immortal because i have no device where i can use them.
Cameras will wear out the SD cards rather slowly, because it will stress the whole card very evenly and doesn't concentrate on one specific memory spot.