I always leave the selvage edges on when I cut my binding strips. When I sew them together at the forty-five degree angle and trim them, the selvages vanish in the trimming. Since I cut one or two extra binding strips anyway, I don't worry about having to locate a number to use to order more fabric if I run out.
If you don't trim off the selvages at some point, I have found that there will be lumpier places along the edges of the finished quilt. I don't like that. Just my two cents worth.