It's been my personal policy to upgrade my computer on Intel's 'tocks' - when it comes out with a whole new architecture. Trying to do a new architecture and manufacturing process shrink was too much risk to be done in one fell swoop. Several years ago, Intel introduced the tick/tock model, where the 'tick' would be a shrink of the existing architecture and 'tock' would be a whole new architecture using the manufacturing process from 'tick.' This was done to spread out the risk.
