I have set the standard font in Excel to Arial 8 (Tools | Options | General).
Often, though, if I add a new column of calculated data - or if I add a new
worksheet - the font size of the new column or sheet is 10.
(I often import data from Access. In Access, too, my default font is Arial
8.)

Apart from giving in an setting the default font size to 10 - I don't plan
to give in to the preferences of some application if I can avoid it! - what
should I do?