'jamin123': on average I clean off the old paste and apply new again every 6 to 10 months; or when I notice temps are getting to what I consider too warm. I use Arctic Silver 5. But no matter what you use, the paste seems to lose its transfer ability and dries out. The more heat you produce the faster the paste seems to dry out. I use 'methyl-hydrate' ( wood alcohol) to clean the bottom of the heatsink and the CPU. A Q-tip or a cotton ball with the M-H on it will get the gunk off the CPU and you won't need to handle it much. When applying the paste; a little is better than alot! Put a blob about the size of a SMALL pea in the middle of the CPU and spread it around until there is a thin coating. Too much will be squeezed out when the heatsink is locked down and the heat applied. This can cause it to run over the edges. You don't want that!