Fade to Silence

There are eight followers that can be recruited, four through events that trigger when you get near, these occur in The Flats, The Peaks, The Prairie and The Pit. The followers that are recruited through events are Vic (Kill a Stalker, find her, Kill 2 Stalkers, craft her a bow), Gani (Perform a ritual), Jin (Kill 3 stalkers while he puts out a fire) and Rhys (Cleanse Totem, then fight him till he weakens enough). Which area they appear in can change, and this also changes where the event is in that area.

The other four turn up at your camp, but I believe only one can turn up for each follower you have recruited through an event. That is to say your first drop-in will only occur after the first follower event, then you won't get a second until you find and complete the second event. I recruited all followers in one run as resources are eventually enough to keep everyone fed and heated, so I am unsure if the drop-ins still turn up if you don't recruit the event follower.