Why Do We Have Daylight Savings Time?

Daylight Saving Time (DST) is a practice that has been around for over a century. It is observed in many countries around the world, where people set their clocks forward by an hour in the spring and then set them back by an hour in the fall. The idea behind DST is to make better use of the available daylight during the summer months and to conserve energy. But why do we have Daylight Saving Time in the first place?