Most people know their distractions but I still come across people or colleagues who have active notifications for e-mail, facebook, twitter and what not. People claim that they don’t get distracted by notifications but I think that’s wrong for most people.
When you have a challenging task at hand, one that’s not too easy nor too difficult to solve, you might be capable of staying in the zone but beware of the time when you have a „standard“ task at hand. How easily are you getting distracted then? No matter what but these tiny notifications let you loose your focus and you know how hard it is to get back on track.

I customized the notifications for Microsoft Teams and Outlook but when I want to really focus on something, I close Teams and Outlook for several pomodoros on this day.

The solution to the problem, according to some people, is on the side of the person who is sending the stuff.  But this is complete bullshit. How can I determine the best moment for you to receive or read my e-mail?
I have heard „Please don’t send e-mails after 6 PM“ in some companies but this leaves me with an open loop until the next day.

In the end it’s your own responsibility to curate the distractions coming into your life. When is it okay for you to get „distracted“ by a new e-mail, notification, whatever?
And, as almost everything else, this changes over time. The number of distractions and how they influence you might have been okay yesterday but it could be too much today. Think about it regularly but not constantly.

You are responsible for your own time, energy and attention!