You just know it when it happens. Like an pair of worn jeans, it just feels good...
Today is the 3.5 month anniversary of my fiance's relocation from Hawaii to Boston. (I know what you are asking ... it's for l-o-v-e, as he says.)
An ongoing discussion is 'adjustments' -- to each other, to East Coast living (weather, pace of life, local idiocyncracies, accents, directions, locations, job seeking) to pets. He seems to have just flowed naturally into it. Of course, having an easy disposition and great outlook on life sweetens any adjustments.
I think you reach a point at any relocation where you just KNOW when it feels like home. Funny how that happens. You just know.