Love all of the hints. I am not afraid to toss a started quilt if I don't love it or if it doesn't work well for me. I do buy good fabric and I have a way to large stash. I sometimes go through and clean out fabric I won't ever use. It goes to a church group that does quilts for homeless or abused women.
When I start making mistakes I stop sewing for the day. I notice I personally decide I want to get the quilt finished and I start hurrying. That is when I have to take it all apart and do it over. Thus my rule to myself is "Stop now! You can sew in the morning!"