Q&A questions from Facebook 2018/11 video 1 of 3

Two weeks ago, I asked you via Facebook for your questions for a Q&A session. I got so many wonderful questions, thanks! I can't answer them all at once so here is the first instalment. I am grouping these questions by topic, not chronological order. Some questions relate to one another and make for a nice stream of ideas when answered together.

Extensive videos covering these and other topics are found on my USB videos:
Andrew's videos on USB