Many Catholics wear these two sacramentals given to us by the Blessed Mother. In 1251, Our Lady appeared to St. Simon Stock, a Carmelite, in England. She handed him the brown woolen scapular and said, "This shall be a privilege for you and all Carmelites, that anyone dying in this habit shall not suffer eternal fire." In time, the Church extended this privilege to all the laity who perpetually wear it. The Blessed Virgin of Mount Carmel has promised not only to save those who wear the scapular from the fires of hell, but also to free them from purgatory on the Saturday after their death, should they go there before entering heaven. There are certain requirements to meet before wearing the scapular. You can find all about it online.
The Miraculous Medal was created in response to a request from the Blessed Virgin through St. Catherine Labouré in 1830 in Paris. The inscription on the medal reads: "O Mary, conceived without sin, pray for us who have recourse to thee." Mary promised to Catherine that those who wear it around their neck will receive great graces. Again, you can read all about it online. I have worn both the scapular and the medal for decades. The fact that I get to know the Lord so well today has to be one of those graces. The Church does not require us to believe in these sacramentals, but they both are silent prayers. Considering the benefits promised by the Blessed Mother, wearing them is a no-brainer.