LOL on the computer, i have a separate folder for each snake, and one master notepad, or word doc with all their information on it as i go along, from what the breeder/seller provided then all information i add to it. if i sell the animal i print a copy of it, and send it along, and i keep my copy in case something is asked after the sale. nothing fancy, but effective, we may switch to printed cards but not sure yet.