We all have some phrases which we repeat too much in our conversations. What do we call it when someone uses a word or a sentence again and again?
We call it a "Pet phrase".
A pet phrase is a phrase that an individual uses repetitively.
As an example:
Whenever his conscience pricked him too keenly he would endeavor to hearten himself with his pet phrase, 'All in a lifetime.' Thinking over things quite alone in his easy-chair, he would sometimes rise up with these words on his lips, and smile sheepishly as he did so. Conscience was not by any means dead in him.
(Theodore Dreiser, Jennie Gerhardt, 1911)