One thing that I haven't seen mentioned here is protecting the backside of the canvas from physical damage. As a former framer I learned the importance of using a piece of cardboard, mat board, or best, acid-free foam-core stapled to the backside of the stretcher bars before applying the dust shield.
That should have been enough to teach me, but years later had one gallery return one of my paintings that had slipped on their wall until the nail caught the canvas, bringing it to a halt with a one inch tear.
Or I should have learned when a different gallery had stacked some of my paintings against the wall with the corner of a smaller framed work creating a lovely square crease on the front of the next piece. (And these are creditable galleries; not the vans parked in vacant lots selling my black velvet Elvis paintings
).
So I'm thinkin' I've learned to either use the foam-core, or paint on wooden panels...