As part of the software carpentry instructor training programme, I did a little screencast on how to use the github webflow:
(post/discussion on software carpentry blog)
I did a little preparation beforehand (preparing the repository and trying it out), but the capture itself took less than a pomodoro (a pomodoro is 25 minutes).
On the one hand, I did not do a lot of editing. On the other hand, the practice I had from doing the video abstract for my Bioinformatics paper really helped here.
I did it all on Linux, using qx11grab + arecord to capture, then kdenlive to paste it together. In this case, I could even just have used qx11grab as it was all a single take.