Why do we change the time every year?

This has been going on ever since 1918.That is why we go through Daylight savings time,and later on in the year,Standard time The claim about this is that it saves energy.But it has been stated and proven that we use more energy no matter what the season or time of the year is.Especially during the summer.There are movements to get most of the world back on Standard Time,but it is not top priority for now.

It is supposed to be due to the longer nights in the summer and shorter nights in the winter, something to do with that, I think.