Bob said:
I see a great deal of debate about font sizes and sizing pages based
on "em" sizing or similar. Is anyone aware of a survey of how many
users (that is, non web developers or similar) actually know how to
change font size in their browsers ?
IMHE, the percentage is ~zero.
I tend to agree. But that opinion is based only on the anecdotal
evidence of my own experience. There are no surveys that I know of. And
such surveys would be of little use, as most web sites are directed at
particular audiences which are not representitive of the general
web-using pubic.
As has been mentioned elsewhere in this thread, the people who badly
need to adjust font size likely already know how to do so. So, it
remains vital that fonts sizes on web pages remain resizable, and that
resizing the fonts does not break the readabilty of the page.
Beyond that, I say use your best judgement based on the font face used,
the content of the page, and the intended audience. Sometimes you will
specify no size at all. Sometimes you will.