Before computerized identification cards, it used to be that my IDs were simply paper cards that were laminated in some plastic using some specialized equipments. It really was not a good idea, I eventually found out, as the plastics covering the card were peeled off, leaving the card in bare. If course you'll have to re-laminate it again under the heat--then it will peel off again after some time. I got fed up and printed some of them (the ones that will be used for a long time) on plastic cards similar to credit cards.
If you believe that it is too impractical to have them printed on cards because you will use them for a short time only, and you are also fed up with heating your equipments and laminating all over and over again, then it would be better to have them laminated not using any kind of heat source--just like these Cleer Adheer Laminating Sheets from C-Line Products.
These laminating sheets are perfect for those who are always on the go and needs to have their ID cards laminated without having the need to use electricity in the process. Don't worry, you won't have to change them often anyway, as they are strong enough they can withstand water, tear, and other external forces. Not even old age can stop from covering your cards. That will not stop you, though, from cutting it and shaping the lamination to your desire.
Of course it would always be best to have them printed on cards but the inks on their face will fade some time, too. And as mentioned above, they are not practical if you'll be using them only for a year, like, say, if you're just an intern in some company.n So for those kind of purposes, there's nothing better to use than Cleer Adheer.