 Just how brief are temporal parts or stages? Typically, objects which have any temporal parts are thought to have instantaneous temporal parts (‘time-slices’), which do not themselves persist through time. (Most perdurantists think that things have non-instantaneous temporal parts too, like you-during-1999.) But an alternative is to claim that an object has only as many temporal parts as it has genuinely differentiated periods in its existence; this is a mixed view, because changing objects will have temporal parts, while unchanging objects and temporal parts will persist without having temporal parts of their own.