What is pepys primary purpose for keeping his diary?

Pepys’s Diary was written for himself only, apparently for the sole purpose of allowing its author to savor once more, at the end of each day, the experiences of the preceding twenty-four hours. There is no evidence of revision of any kind, and the book was written in a shorthand that protected it from posterity for more than a hundred years after its author’s failing eyesight forced him to give up keeping his diary.