I always match my thread, it is a left over habit from sewing clothing.

I like to keep my bobbins clear so I use up left over bobbin thread when I piece things. Then, I use cone thread that is a neutral. Right now I have lots of bobbins with some thread on them because of raw edge applique that I used to make some Christmas gifts; I will have a piecing good time after the holidays. I use matching thread of quilt on the front of my projects. I like to use Bottom Line thread when I stitch in the ditch. I also like 30 or 40 weight thread to quilt my designs.

Please make sure that you are testing the thread for breakability. Old thread only gets older and can make a quilt come apart after only a few years or any tugging that goes on when sleeping. Just saying...

I use up all my partial bobbins when piecing then wind partial spools of thread onto the bobbins to use them up also. I tend to use cones of thread for top sewing so I don't have to thread the needle too often. LOL

Not sure what you are sewing, I don't worry so much with piecing, normally its gray, tan, neutral or beige and it blends in well. When I'd doing clothes I try to match or do one shade darker than fabric for the thread. Serging, I only make sure the needle threads match and not worry so much about the loopers.