Father Fortea over at Catholic Spiritual Direction answers the question of whether one can be condemned for “little” sins?
A. No. Eternal condemnation is so horrendous, so terrible, that it is reserved for grave sins. Only one who dies in a state of mortal sin is condemned to hell. This being said, every sin, no matter how small, is a step toward greater sin; every sin, no matter how slight, is a step in the direction of condemnation. No one can say: “I will only commit this small sin once and I will never do it again.” Every sin weakens the will, and every fault darkens our understanding a little more. Great sins would not exist without small ones. In its essence, every deliberate sin is one step closer to the precipice, one step closer to eternal damnation.
Some people are under the impression that avoiding “little sins” is just something bishops, priests, and consecrated religious need to be concerned with. These same people claim that laypeople do not need to watch out for venial sins because, after all, they live in the “real” world. This is a serious error. Though venial sins cannot directly cause us to lose our salvation in Christ, we need to avoid them nonetheless. Little sins weaken us and can lead us to commit great sins. Jesus calls every Christian to be holy, to “be perfect, as your heavenly Father is perfect” (Mt 5:48). There can be no room in our lives for deliberate venial sins.