This pattern is used when you want to emphasize that an action is done thoroughly, from start to finish, with persistence. It can suggest endurance—like pushing through something difficult—or just doing something completely without giving up halfway. For instance, you might use it when you finish a long book or survive a tiring workday.

Think of 通す as meaning 'to pass through'—you pass through the entire action to its end. It's often used for things that require effort or time. The verb that comes before it is the action you're completing. A common example is 押し通す (push through), meaning to force your way through to the end. But it's also used in everyday speech with verbs like 読む (read) or 働く (work).

Because it emphasizes completion, it's not used for short, quick actions. You wouldn't say 食べ通す for eating a snack—that sounds like you're eating without stopping for hours. It's more about a significant process or an action you stick with despite obstacles.