To remind students with math: Morning, afternoon, evening, and night are the four parts of the day. The time to spend on your thesis is certainly 2 sections per day for a thesis to be completed in 2 years for a master thesis. Thus, for those who spend only 1 section per day on study, it will take 4 years. After LW's case, I no longer accept any deals on graduation but just follow the plan I supervise.
Likewise, if a MS student spends less than one part of a day continuously, the study time very likely will beyond the max time allowed.
The rule is applied for PhD students by adding a factor of 2.