The purpose of this meeting is to discuss important issues.

Means to an end are sometimes necessary to achieve a goal.

The end justifies the means.

This discussion is useless.

It is advisable to create a packing list before the trip.

The purpose is to protect the environment.

Purposes are important for planning.

For what purposes do you use this device?

I stuck a thumbtack into the wall.

This backpack is more practical than the other one.