About a couple of weeks for me. I was coming from an LG G2 which has a 5.2" screen, I'm 6'4" and would consider my hands pretty big. First few days were tough adjusting, I was really thinking I may have made a mistake getting the 1520! I found that the way I had been using smartphones for the last 4 years was going to have to change! I would rarely use 2 hands when using an LG G2 but after a few days with the Lumia 1520 I found that using 2 hands was the way to go for a lot of activities. Things like typing especially really require 2 hands, now I can type as fast if not quicker than on my old G2.