Tip: if you are going to change theme as well, do that first and then change default font.
10
or greater than 14
: depending on your recipients' age and screen resolution, sizes outside that range may appear near illegible, or obnoxiously large.Tip: plain text contains no formatting, so this setting is cosmetic and only affects your copy of Outlook, not any message you send (those will use the recipient's email program settings).