For piecing I still use more off white than anything else because the majority of my fabric is light to medium color. Still, I have spools of camel, tan, beige, lt. blue, pink and gray that are used mostly for the actual quilting. If my adjoining seams are off a 1/16" or 1/8" I will try to adjust that only once. I'm far from perfect, and believe that every quilt should have a small mistake in it somewhere. The thing that bothers me is not back stitching at the end of a seam and then have it pull apart when the block is trimmed. Can't tell you how much time I spent on my latest quilt repairing pulled apart seams.
Oh, and I'm never up on the latest patterns and stay far away from those that seems complicated to me as my brain just won't wrap around those. The most current pattern from a couple years ago was the potato chip quilt and I did use scraps to make one, but have yet to quilt it.