Why is it important to separate material from mixture?

Mixtures are impure substances with the following properties:

Their composition is indefinite i. e they consisit of two or more elements or compounds in any proportion by mass. Their constituents retains their identity i. e physical properties are retained. They can easily be seperated by physical methods into their constituents.

It is important to seperate materials from mixtures because mixtures do not undergo chemical changes when they combine. This implies that they can easily be seperated using simple seperation techniques with the constituents still retaining their properties.