Sorry to keep harping on this, but the following quote from this 43Folders post is worth repeating…

“An email auto-check set for every minute means 60 potential distractions every hour, or almost 500 per day. Look back at a week of your emails and ask yourself: how many distractions was that really worth? How much crucial, instantly actionable email did I receive to make it worth shifting my attention over 2000 times?”