if it is a sin to wear a Rosary, he say it depends on the intention.
I had a parishioner who was "cared for in the community" whose hobby was to wander around London and kiss crosses at the time when it was fashionable for women to wear large plain sparkly crosses. Her favourite hunting area was Sloane Square. I used to tell her she would get sectioned, she used to tell me her score. Her best was 38. Most of her life she was perfectly ordinary civil servant but for a couple of years she had this mania to discomfort the comfortable.