Is a Catholic required to receive the Sacrament of Reconciliation at least once a year if he/she has not committed a mortal sin?
No. Church law requires confession only of grave (mortal) sins at least once a year. If a person has committed no mortal sins, he is not obligated to go to confession. Code of Canon Law (CIC) states, “After having reached the age of discretion, each member of the faithful is obliged to confess faithfully his or her grave sins at least once a year” (CIC 989).
That said, “It is recommended to the Christian faithful that they also confess venial sins” (CIC 988.2).
Is confession good for anything other than the absolution of mortal sins?