"It takes about three years."
"Three years?" He looked shocked.
"It usually does. It's a different world. You have to get used to a paler set of colors, a quieter lot of sounds. You have to allow for relapses. All the people you used to know well will get to be just a little strange. You won't even like most of them, and they won't like you too well."
Three years? Well, hell, three weeks down.