Convert the given sentence into indirect speech.
She said, "I have often told you not to waste your time." 

The correct statement is "She said that she had often told him not to waste his time." The first person pronoun “I” is replaced by third person pronoun “he” and the second person pronoun “you” and “your” are changed into “him” and “his”. "That" is added and the present perfect tense is changed into past perfect tense.