It greatly depends on your job, and it doesn’t have to be a glamorous job, just one where people request things of you or you of them. For example, a friend is a corporate buyer, somewhat low in his organization, and receives about 120 emails from humans each workday. (His strategy is to select all the emails he will handle that day, put them in a folder, and call himself done when that folder is empty. I.e., he almost never sends a same day response.)