I'm not sure if an "unexpiring" cookie is possible, but you can make them last a very long time simply by multiplying the time they last. Such as with " 3600 24 365 * 10 ". 3600 would be 1 hour, 24 would make it one day, 365 would make it one year, 10 would make it one decade, ect., ect. I hope this helped.
