That's a nicely illuminating post David.
And I wonder if it's worth being used as a "sticky".
I'm thinking about the many queries we get from folk asking where they can get 0.25 coupling capacitors etc. If it helps a few its worth it and people could perhaps be pointed that way to help them understand a few things, maybe with an explanation of tolerance bands and why exact values aren't always that critical, depending on application?
Excellent post David
Andy.