GP's post also discounts cases where the manufacturer is just wrong about a spec. I once ordered a custom aquarium. 200+ gallons, over 400 pounds of glass. The

GP's post also discounts cases where the manufacturer is just wrong about a spec. I once ordered a custom aquarium. 200+ gallons, over 400 pounds of glass. The sizes were standard, custom part was for drilled holes for plumbing. The manufacturer advertised the aquarium as X inches by Y inches foot print. I built a stand for that size, but it turns out the manufacturer was half an inch off in each direction. I couldn't return the aquarium since it had been made custom, but the manufacturer delivered me a product I couldn't use with the stand I built. The stands have to be built very specifically to transfer weight to the floor. Filled, the aquarium was over 3000 pounds, being off by half an inch was catastrophic. I had to tear apart the stand I built and rebuild it to support it. Manufacturers can be wrong, manufacturers can lie. A microwave might fit your cabinet on a spec sheet, but not when it's delivered. Or something else might make it a poor fit (i.e., it fits, but requires clearance you don't have for the door hinge to swing). Let customers return things.