Almost all cards come formatted nowadays. Once photos are transferred to computer, moved rather than copied, the card is ready to re-use and there should be no need to format it.
I've had a couple of cameras, as well as family members with their cameras, and the only time I've had to format a card is after a screwup - wife taking the card out of the camera with the camera switched on!!!!!! daughet taking card out of the camera and laying it down near a magnet!!!!! Bith guaranteed to lose pictures and possibly screw the card.
Always formatted from within the camera.