Don’t know if you’ve answered this, your wildlings as exiles reminded me of something that’s been bugging me for a long time: what is the timeline of the Others return, specifically in regards to Craster’s involvement in that? Could it be that there had been other people doing what he did? It’s not mentioned how long Craster has kept his wives and has had non sons to speak of, how much of the Others’ return is his “fault”? Thank you in advance.

Good question! Craster is in his late middle age/early old age, probably late 50s through mid 60s. So that gives a rough sense of how long he could have been doing it. The difficulty is that we don’t know how long the White Walkers have actually been “accepting” his sacrifices – could be they came along after he started doing them. 

In terms of it being his fault, the fact that Jon III mentions that things have been changing recently, with the Cold Gods coming more frequently and Craster having to sacrifice sheep suggests that there’s some exogenous change going on.