This pattern expresses that someone does something, then does something else, and this cycle repeats. It often carries a nuance of the speaker's irritation or feeling that the actions are pointless or unproductive. You'll commonly hear it in complaints or descriptions of bad habits, like 'She keeps starting and stopping' or 'He keeps going back and forth.'

It is not a neutral listing of habits; it suggests a lack of progress. For example, if you say 書いては消して, it implies you're not getting anywhere with your writing. The repetition is key—using it only once would not work. The pattern is more common in spoken Japanese when complaining, but it can also appear in written narratives to depict restless behavior.