I think this is a good question because it's a focus of my research! It seems like some individuals behavior changes. Some old male chimpanzees become less social, travel in smaller parties, and participate less frequently in behaviors like territorial boundary patrols. Looks kind of like retirement. But with the females? It's less clear. Garbo is definitely exceptional for her gregariousness, however, since not all females patrol regularly at any age. Thanks @ekpickle