When you get a new Rosary, take it to a priest and have it blessed. Remember, the blessing of the Church on your Rosary makes it a sacramental. That means when you use your Rosary beads with devotion, you receive the help of the entire prayer of the Church. Using a sacramental brings special help from God to grow in holiness.
To foster the love of and universal use of the Rosary, the popes have given priests the power to bless the Rosary, and when they do each bead carries with it an indulgence.
"An indulgence is a remission before God of the temporal punishment due to sins whose guilt has already been forgiven, which the faithful Christian who is duly disposed gains under certain prescribed conditions through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints."
"An indulgence is partial or plenary according as it removes either part or all of the temporal punishment due to sin." The faithful can gain indulgences for themselves or apply them to the dead.
An indulgence is obtained through the Church who, by virtue of the power of binding and loosing granted her by Christ Jesus, intervenes in favor of individual Christians and opens for them the treasury of the merits of Christ and the saints to obtain from the Father of mercies the remission of the temporal punishments due for their sins. Thus the Church does not want simply to come to the aid of these Christians, but also to spur them to works of devotion, penance and charity.
Since the faithful departed now being purified are also members of the same communion of saints, one way we can help them is to obtain indulgences for them, so that the temporal punishments due for their sins may be remitted.