With a drawer type file cabinet, the file folder label is on the top tab of the folder. Because of this, you can only go four or five drawers high. If you had drawer any higher than the fifth level, it would be difficult for the average person to retrieve records from that drawer. 

With a drawer filing system, the user not only has to be taller than the drawer that he or she is pulling from, but they also have to lean over the drawer to see the file folder labels. With lateral filing, you can go seven or eight levels high with the same height person. The colour coded edge labels save time and energy for staff looking for or returning files.