I have always marked as I quilt. I find that most markers dissapear all to soon. I do have one of those gel pens made for marking quilts and only go away with heat! Dryer heat or Iron heat! thinking of marking the center of the blocks on my new quilt top with that and quilt in the ditch for the rest of it. That way I can use a light box and the pen for marking those. They say the marks will come back at 14 degrees but since the quilt is going to Florida (wish I was there) I don't think I have to worry about it. LOL