For larger jobs I give the option of 3mm glass pr 'Artshield' scratchproof acrylic, which is expensive - we don't stock normal acrylic/perspex - because we don't like it - it scratches too easily.
So, most times the customer goes for the 3mm glass - which I buy cut to size.
Today I framed a 1.5 x 1m poster by myself - a two man job at some stages but my framer is still off sick.
Half way through fitting this heavy stuff into the frame, swearing and sweating, I thought 'why am I giving a money-saving option which causes me so much grief'
Then I dragged the frame, face down, when I should have lifted but could not by myself and trashed it - I had a blanket on the bench but somehow a rogue screw found its way on top.
So - that's it - no more 3mm glass - I'll take on normal 3mm acrylic, which will be dearer than the glass but cheaper than the artshield and give the customer the option - clear or fuzzy after a few cleans!