Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150723053637/@comment-80.64.127.5-20160906103631

Is the concept of "aging" itself that is hard to apply on a Space Marine. The Sus-an membrane allows them to enter a state of hibernation that can last over 500 years, saving him from even mortal wounds. Considering this organ works by sealing and protecting the SM neural architecture of his body, this will make a SM vistually immortal, since almost every other part of his body can be healed or replaced. Thats the reason why some Dreadnough are so old. They are ofteen kept is such stasis.

Probably, a Space Marine that stay 100% active in a combat zone for all his life will show "issues" after 10000 years, but considering time spent to travel, and to replenish ranks of his companies after a battle, or just scouting/guarding tasks, it is very hard to say how long they can live.