I keep scraps for applique' which often only needs the small bits. They're jumbled in a shoebox. Who cares? If I need it, I'll iron it.
Larger scraps don't get cut into squares. Tried that. They're still squares. And probably will be for a Looonnnnnggg time! My larger scraps stay together...all colors...I sort through when I'm making a prayer pocket quilt.
I do try to make my quilts the best I can.
Instead of following 'don'ts,' try the 'dos.' As in do:
enjoy quilting, keep learning new ways, get rid of things you're not going to finish, take pride in your work, enjoy meeting other quilters.