The first day we put in insulation I didn't wear a mask. Um....the second day, which was today and Margaret helped me, I wore a mask. Just the little blue kind you would use for light duty dust. It made a huge difference. Insulation is no easy task, although it seems easy enough. A lot of bending, climbing on ladders, cutting and UGH! the staples. When the staple gun worked, it was great! But like our computers....when they don't work.....things get ugly. :) We made it through and she and I will hopefully complete the task on Monday.