how often do you update it?
Some people just dont touch it until the time they are job hunting again, many are just scared that if their employer finds out or see their updated Resume , they might think you are planning to leave them .
Than again, there are others who keep it updated with every development in their career and they do it to stay on top of the game and be kept informed of market opportunities at all time. They also do it coz their Resume is in essence their brand reflection.