1. It's only one data point, but here's a chart of my typing speed while learning a new fully custom layout: https://xsznix.files.wordpress.com/2016/05/screen-

1. It's only one data point, but here's a chart of my typing speed while learning a new fully custom layout: https://xsznix.files.wordpress.com/2016/05/screen-shot-2016-05-16-at-16-25-03.png https://xsznix.files.wordpress.com/2016/05/screen-shot-2016-... 2. I use QWERTY on mobile devices, Dvorak on standard keyboards, and RSTHD on split ergo keyboards, and I can switch between all of them without any hassle. It helps if you use a different keyboard form factor for each layout, but even if not, I don't think it's difficult to maintain adequate fluency on QWERTY when you need to use someone else's computer.