If you do bring your curling iron, hair dryer or laptop, you might want to bring an adapter, although the vast majority of ships run on 110v. If you do forget to pack a personal effect or two, don't panic. Even the smallest, no-frills ships have at least one small shop on board, selling stuff like razor blades, toothbrushes, sunscreen, film and other things you may need. Some ships, like Carnival, Crystal, Princess and Holland America, have self-service laundry rooms on board so you can wash, dry, and iron your own clothes for a few bucks. If you like reading but don't want to lug a couple of fat novels on board, don't.
Most ships have libraries stocked with books and magazines.
You're also likely to find paperback bestsellers for sale in the ship shops. All rights reserved.