Do we need to write all the distractions or the major ones during the session? How do we prevent the same distractions from coming back?

I would write down only the major distractions. There are things like thoughts that distract you when you’re working, but like clouds in the sky, they float by.

All of them even the small ones can bug you. This way you fully free up your mind to fully focus on the current task. When you write down all distraction you will see how much time you waste on distractions.

From my point of view, better to show the major ones. When you launch lots of goals, sometimes you can’t reach all of them. It hesitates you. But if you see that you’re just on the right way, only few things undone, you don’t feel worried. You try to think that tomorrow will do all.

For me personally, the distractions are often tasks that I haven't completed yet. So they are important to write down. Writing them down also makes them more concrete, which makes me less likely to forget to complete them. Also it feels a lot better when I can fysically check the task after completion.
But when the distraction is a less clear task, the situation is slightly more difficult because you need to halt your train of thought more intensely.
Small distractions like, I like that shirt of the person sitting across from me are distractions I tend not to write down. This is because I don't mind them as much and they make me feel present.