The screws to fit the top halves of the 3 support bases to the bottom halves do need some strength to push in through the metal hole for those that are putting it together manually instead of with an electric driver. But it wasn't too hard and the whole structure is very sturdy. I can actually see it being used outdoor in the patio for plants and gardening supplies too since the racks are metal with holes, and easily washable. Have not tried to see if it's going to rust though. 
Assembly time for an amateur: about 30 min