I was at first surprised that your guest receives 600 e-mails per day, then I spoke (in person) with my college professor daughter who estimates she gets over one hundred e-mails most days.
Being mostly retired (I'm 65), I find my e-mail needs are minimal. I use a 'family' account which we have had since the dawn of the e-mail age, which my wife also checks. I clean out the junk about twice a month, and rely on her to notice anything directed to me; sometimes I find personal e-mails which were missed. Once I showed up for an appointment which had been cancelled by e-mail.
I am a deliberate late adapter, but I have been recently dragged into 21st century communications by my wife, (wanted a smart phone to stay in touch 18/7with students she mentors via Facebook. This lead to G-mail, then my daughter wanted us on Google Hangout. Then I discovered there are free Internet music sites e.g. Spotify, TuneIn, so I had to get on Facebook.
So I,m being drawn in, in spite of myself, but I'm trying to limit my time spent.
More information about text formats