Paretoprinciple

Meanwhile a small all-time-rule:

The Paretoprinciple also known as 80-20-principle

Most of the work (80 percent) is done in a very small part of the complete project-time(20 percent), but to complete the project, to do the rest (20 percent) a very long time (80 percent) is needed.

A link to the German explanation:

http://en.wikipedia.org/wiki/Pareto_principle http://de.wikipedia.org/wiki/Paretoprinzip