From a design standpoint, however, drop-down menus are an excellent feature because they help clean up a busy layout. If structured correctly, drop-down menus can be a great navigation tool, while still being a usable and attractive design feature.
drop-down navigation menus can be user-friendly. Recently Jacob Nielsen the results of his recent drop-down menus study, in which he found out that big, two-dimensional drop-down panels that group navigation options help users to avoid scrolling and can precisely explain the user’s choices with effective use of typography, icons, and tooltips.
Drop-down menus do in fact organize content into small, uncluttered elements, but if not done correctly, they can be just as bad as a messy layout.
Avoid a Drop-Down with More than Two Levels
Option 1: Hover Menu
Basically, there are two ways to approach the drop-down menu: with either a hover or a click to activate the menu. From a design and convenience standpoint, a hover menu is better.
Option 2: Clickable Menu
On the other hand, many will argue that a clickable menu is better because it is much more usable. Reason? Because of the way a hover menu is constructed, the user has to have the pointer over the menu at all times. If the user loses focus of the hover menu, it closes. Therefore, it is better to go with a drop-down menu that is activated by clicking a button, then deactivated by clicking the button once more.