Not as many as outgoing. But then that is the nature of Volunteer work. They love you when they need you, but otherwise you're backburner until the next crisis.
Zero....I'm retired, and my work e-mail address was discontinued by the firm a few montbs after I left (they left it open for a little while until the people who were still sending e-mail to me were informed of my retirement).
None. I've been retired a long time. But I never paid much attention to work emails. The only time I looked at them was at work and if I was there I had stuff to do.