STA found that 53 percent of mobile site visits are abandoned if a page takes longer than 3 seconds to load. Nielsen Norman Group reports that users often decide whether to stay within 10 seconds when the value of a page is not clear. The 3-click rule is debunked by Spool and UIE in 2003: the number of clicks does not by itself predict task success. The Doherty threshold shows that response under 400 milliseconds keeps users engaged.