It&#x27;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.<p>That said, I&#x27;m back on qwerty because my wrist is OK now and it&#x27;s just less hassle when using multiple machines over which I have less control.<p>Also, anecdotally, when I made the switch I was in my mid 20&#x27;s.  I tried the experiment again (albeit with Colemak) a couple years ago in my late 40&#x27;s and after 2 weeks I was still struggling so gave up.<p>I don&#x27;t know if age had anything to do with it, but that&#x27;s one big difference between the 2 times.