Your computers will collect an inordinate amount of dust if left alone. Yearly, and sometimes more frequently especially if you have pets in the house, the dust (and anything else that doesn’t belong) should be blown out. For laptop and desktop computers, the case should be opened and the fans checked. A fan with encrusted dust will cause the device to work harder and hotter, overheating even and causing it to shut down at an inconvenient time. A $10-$15 can of compressed air and 15 minutes of time can prolong your computer’s usefulness.