Okay, you have a work pc, a MacBook and an iPhone.
You have one email address,
example@123.com
setup each computer/phone to download emails from the server of the email account. Set it to leave the emails on server after download, for 30 days.
This means if you go on holiday for 2 weeks, when you come back you can still get all emails you miss on all computers.
Does that make better sense?