What switching actually costs

Every switch between tasks carries a cost that is invisible because it happens inside your head: the previous task is still partly loaded, and re-entering the deep part of the new one takes several minutes. Do that twenty times in an afternoon and the afternoon is gone with very little to show for it.

So a notification checked "quickly" is not quick. Its real cost is the re-entry afterwards, which is why the useful move is removing the possibility rather than resisting it — phone in another room, one tab open, notifications off for a bounded block.