Google will begin issuing its users cookies in coming months that will be set to auto-expire after two years, while auto-renewing the cookies of active users so preferences are not lost. This change is in response to pressure from users and privacy advocates. Google notes that users will continue to have control over cookies via their browsers.
WebCopyPlus
604.295.0100
I don’t think cookies will last for 2 years on anyone’s computer. Many people use anti-spyware utilities on a daily basis which would wipe out all of the cookies on their machine.