When and how to install cross-braces on a shelving unit?
I purchased an "industrial" shelving system that I will soon install in my home. Each unit will be separate and measures 7 feet high, 4 feet wide and 2 feet deep. Each will have 5 shelves that can hold 600 pounds each. They can be bolted or clipped, but I prefer to use the clips (unless instructed otherwise by a guru). I'm not going to put anything much heavier than books on them.
I was assured by the seller that the units did not need bracings, but everyone else tells me otherwise. So what's YOUR take, fellow instructables member? How can you tell if a shelving system needs braces? If so, where do you put them? At the back back or on the sides? Full length (7' x 4') or any size but in the middle of the posts?
Thank you very much!!