Consistency is enough for some quilts, but not when different types of patches need to line up within a block, or when different types of blocks need to line up within a quilt. The important thing, as Pagzz said, is to use a seam allowance that gives the expected measurement for each patch within the block, and therefore for the completed block. Often this means sewing a scant 1/4" from the edge of the fabric because the thread and fabric thickness can mean that a full 1/4" seam allowance will leave less fabric in the patch. It's only a thread or two, not enough to endanger the integrity of the seam.