Synonyms: The Three-Click Rule
It is a common-known rule, saying that it should take not more than three clicks or taps to complete a task on the website or in the app.
There are not so many studies that can confirm the 3-Click rule. In fact, there are more studies against it. In practice that means that you don’t need to follow the rule all the time, but sometimes it can be helpful.
When it comes to navigation, you can also use the 1-Click Rule. It states that every click should take a user closer to his goal without any distraction. The amount of clicks is not so important. This rule seems to be more useful in practice as sometimes we deal with complex products in terms of hierarchy and navigation.
When a click leads to a new page, this page should load as fast as possible. It is better to have 5 fast clicks than 3 long ones.
Sometimes it is better to have more than 3 clicks. For example, when you have a big form it is better to take 5 steps to fill it. But make sure that a user understands how many steps he needs.
Pay attention to words. It doesn't matter how many clicks you have. It is always more important to ensure that a user understands the meaning of each one. Avoid unfamiliar or vague words in menus and buttons.
Make navigation as simple as possible. Try to avoid multilevel menus. Too complicated hierarchy makes people feel uncomfortable.