Standard lamination runs five mils per side, ten total, wrapped around a card stock rectangle measuring three and three-eighths by two and one-eighths of an inch, the same dimensions as a credit card by a coincidence of mid-century manufacturing standards rather than any coordination between the two industries. The library card predates most of what now shares its wallet slot and has never adjusted its size to compete for the position.
A first lamination holds for roughly three to five years of ordinary handling before the corners begin to lift, exposing a sliver of the paper card beneath to whatever pocket lint or wallet damp happens to be nearby. The barcode is the first casualty. Scanned daily at some branches and monthly at others, its black bars wear pale at the same three or four stripes each time, worn by the same angle of presentation at the same scanner, until a librarian squints and keys the number in by hand instead.
Card, laminated: the phrase suggests a permanence the object rarely delivers, since a lost card, a name change, or a redesigned logo will retire it well before the plastic itself gives out. Children's cards, printed smaller and in brighter colors, turn over faster still, outgrown less by wear than by the simple fact of eventually getting a driver's license and needing the wallet slot back. The library issues a new one without ceremony each time, the laminator running the same five mils over a fresh rectangle, indifferent to the count of cards that came before it.