Most 'factory defects' are biography: written on site between delivery and install. Storage discipline keeps biographies boring.
At the tailgate
Open-count cartons against the packing list, photograph any carton damage before signing, and note it on the POD — that sentence is the entire claims process working for you.
Stacking physics
Flat on a level base with full-sheet separation, or near-vertical at a slight lean on padded rails; never on edges or corners, never more than a modest stack. Gloss faces get their films left on until hanging.
Climate and clock
Store where people would live: finished interior, normal humidity — never garages, basements or sun-through-glass rooms. Weeks of correct storage are harmless; the enemies are moisture cycles and other trades' ladders.