MRD, my optometrist said it takes 2 weeks, but I found it to be a week or so. You have to get used to adjusting your head postition and where you look. After a while your body does it automatically. Watch yourself of the stairs!! I almost took a header. The only problem I have now is if I go between contact lenses and the glasses. Takes a few minutes. Watching TV in bed is hard unless you slide them down your nose. You'll get used to them.