It's less than you might think. I did a complete switchover to Dvorak to ameliorate some wrist issues and was back to my normal speed in about 2 weeks. I surp

It's less than you might think. I did a complete switchover to Dvorak to ameliorate some wrist issues and was back to my normal speed in about 2 weeks. I surpassed my qwerty speed by about 20% according to my own tests before and after. That said, I'm back on qwerty because my wrist is OK now and it's just less hassle when using multiple machines over which I have less control. Also, anecdotally, when I made the switch I was in my mid 20's. I tried the experiment again (albeit with Colemak) a couple years ago in my late 40's and after 2 weeks I was still struggling so gave up. I don't know if age had anything to do with it, but that's one big difference between the 2 times.