Because of their portability, laptops are subject to more wear and physical damage than desktops. Components such as screen hinges, latches, power jacks, and power cords deteriorate gradually from ordinary use, and may have to be replaced. A liquid spill onto the keyboard, a rather minor mishap with a desktop system (given that a basic keyboard costs about US$20), can damage the internals of a laptop and destroy the computer, result in a costly repair or entire replacement of laptops. One study found that a laptop is three times more likely to break during the first year of use than a desktop. To maintain a laptop, it is recommended to clean it every three months for dirt, debris, dust, and food particles. Most cleaning kits consist of a lint-free or microfiber cloth for the LCD screen and keyboard, compressed air for getting dust out of the cooling fan, and cleaning solution. Harsh chemicals such as bleach should not be used to clean a laptop, as they can damage it.