A little theology:
inside the sacrament of penance, imperfect contrition is sufficient for the forgiveness of sins. That means that a less than perfect love for God and perhaps an inkling of the fears of the Fires of Hell or loss of Heaven are involved.
Outside of the sacrament, perfect contrition is required for the forgiveness of sins. An act of perfect contrition consists of deep sorrow out of pure love of God–no other motives or strings attached. Naturally, an act of perfect contrition is very hard to make, and even when a person attempts to make one, they are never sure if it actually was perfect.
The Pennitential Rite is not Sacramental–there is only one sacrament offered during each Mass, the Eucharist, unless another, like a bapitsm or marriage, are inserted within the context of the Mass.
This means that unless your friend makes an act of perfection contrition (a rather fuzzy thing, and highly unlikely) at every Mass, she still has sins on her soul.
Also, regardless of what happens at the Pennitential Rite, many Holy people throughout history have reiterated the great benefits of confessing all venials sins, including Padre Pio, patron Saint to many here on the forum, who advocated weekly confession. Why so often? “Even a room that has been shut and has had no one in it for a week gathers dust.”
Also, Canon Law says that every Catholic must confess grave sins at least once a year, and if your friend is like most people, she commits at least one mortal sin in the run of the year.
