Designed for Use: Create Usable Interfaces for Applications and the Web

Don’t get drawn into endless research. At some point, you have to take a leap of faith, try something, and see whether people find it useful.

rule similar to the “the fewer clicks, the better” rule is that you must constrain the number of options given to the user; do not make her choose from more than seven options. The reason given for this idea is that humans are incapable of processing more than seven possible choices. Like the “fewer clicks” rule, this rule is wrong.