Sometimes, my layers don’t stick nicely, or I print a part that’s too thin, and the part cracks between layers when I try to use it:
There’s no need to throw them away and reprint them. Just use a q-Tip soaked in acetone and paint it liberally. Junk ABS bits dissolved in acetone works even better, but then you need to have a different bottle for each color. I keep it in a glass tea trea oil bottle from Trader Joe’s. The milky white appearance of the liquid in the jar is due to the natural ABS that I dissolved in it. Don’t bother buying expensive ABS glue. Make it yourself!
Sometimes, I’ll just paint the sections of a part that look weak, even if they haven’t yet broken, as a pre-emptive measure. It makes your parts glossy, too, if you like that.