The most common habit among people that you and me would have observed is that of setting the time in the watch few minutes ahead of actually what it is. People have this feeling that if they see the time earlier than what it has to be that shall help them do lot of work much ahead of the deadlines. It is as if you deceive your own mind that you didn't set the clock ahead in time and it was the real time to trigger the sense of urgency. But still you will find that one who does this would have completed the work only by the deadline and feel happy that if the clock was set right s/he would have been late to complete the work. Let me reveal the logical reasoning here.
The human mind plans every work on a rough calculation basis based on past experience and motivation levels of the present. For example you may estimate the time to brush your teeth as 5 minutes and time to take bath as 15 minutes. This follows for all the activities that we are involved in. Seldom we remember that we are not the only deciding factors for things to happen. There are multiple external factors that shall also contribute to the early or delay in completion of work at hand. Unfortunately not may of us account this for calculation and end up blaming ourselves for not planning properly. So any work will have to be set some extra tolerance limit than the time you estimate it to take. By setting the clock ahead the human mind gives space for the influence of external factors or I can say that it sets the extra tolerance limit. So instead of setting the clock ahead of time if one can plan out the extra time required as tolerance all work can be accomplished using the real-time clock itself.
Tolerance limit need not be only with reference to time. Tolerance in terms of budget planned for household things, tolerance for the extra information needed to complete the deal, tolerance of having extra resources to complete any work are to be well-planned and included even before execution in order to avoid any further tensions or delay or loss of work. Plan your resources, time and goals with tolerance limits so that even if you save on few they can be used in the future. You can participate in feedback sharing on firstname.lastname@example.org