Sometimes I wonder if I should mention it in confession more often but it’s not all that clear when the line is crossed except in obvious circumstances.
I know the obvious example (which feels like grave matter too) where you plan to sin because you’re going to confession anyway. In this case is the sin incurred when that thought enters your mind? What else could be presuming? When you put off confession till a later time because you “know” you’ll receive God’s absolution?