There are two types of knitters: perfectionists and fix-laters. (There are actually many more types of knitters, but the purpose of mending, there are two).
The perfectionist is the knitter who goes back as soon as there is a mistake. If there is one extra stitch or one stitch to few, the perfectionist will search through the rows for the missing or rouge stitch until it's found.
The fix-later is what I am. While I'm knitting I prefer to keep moving forward and come back later. If I find an extra stitch, I just K2tog. Missing stitch? M1. This method, though it produces a faster result, requires quite a bit of touch ups once the knitting is done.
That, my dears, is what I'll be doing tonight. Mending the holes where my lace pattern was off, weaving in endings, and repairing the holes around the thumbs of mittens. Somehow I never can figure out how to knit a mitten without a hole between the hand and the thumb. Project!