Laptops rely on extremely compact cooling systems involving a fan and heat sink that can fail from blockage caused by accumulated airborne dust and debris. Most laptops do not have any type of removable dust collection filter over the air intake for these cooling systems, resulting in a system that gradually conducts more heat and noise as the years pass. In some cases the laptop starts to overheat even at idle load levels. This dust is usually stuck inside where the fan and heat sink meet, where it can not be removed by a casual cleaning and vacuuming. Most of the time, compressed air can dislodge the dust and debris but may not entirely remove it. After the device is turned on, the loose debris is reaccumulated into the cooling system by the fans. A complete disassembly is usually required to clean the laptop entirely. However, preventative maintenance such as regular cleaning of the heat sink via compressed air can prevent dust build up on the heat sink. Many laptops are difficult to disassemble by the average user and contain components that are sensitive to electrostatic discharge (ESD).