Duration

Pg.178 "How long will you have to endure this primitive existence? How long before the walking dead simply crumble to dust? How long before life can return to even a semblance of normality? Sadly, there is no exact figure. The first zombie to rise will, unless it is frozen, embalmed, or otherwise preserved, completely decompose after five years. However, by the time the undead have world domination, ten years might have already passed. (Remember, you will be fleeing when the war begins, not at its end.) When zombies truly dominate the planet, and there are no more fresh humans to infect, it will truly take five years for the majority of them to rot away. Dry climate and freezing will preserve many, keeping them functional for, potentially, decades. Bandits, refugees, and other survivors like yourself may become further prey, adding a newer but smaller generation to the older, decaying horde. By the time these turn to dust, the only undead left will be those preserved artificially or constantly refrozen with each winter. These you will have to watch for decades to come. Your children and even your children's children will have to be wary of them. But when will it be safe
to come out?"