I use large spools in 5 basic colors for piecing, not cones. I have nothing against cone thread - just don't know where to buy 50# cotton thread in cones. The cotton thread cones I've ordered in the past, I have returned because the thread is too thin (clearly intended for serging). There's a reason why 50# cotton thread is recommended for quilts.
My 5 basic colors are black, white, light gray, medium grey and beige. I do buy matching thread if the overall quilt color is a specific color, say a mostly blue quilt will get blue thread.
I haven't been able to regularly sew in the past couple of years, but under normal conditions, once a year, I take all my partially used spools used for quilting and sew up a scrap quilt until I run out of thread. My sister occasionally gives me thread that is part of a auction box, but I normally use that only in car quilts where I'm sewing to a foundation. I had too many seams pop due to old thread and it's a nonissue when you sew to a foundation.