If you're in a poor signal area and your location services are on, that can drain your smartphone battery far more than if you're in an area with strong signal.

Does location services use a lot of battery?

Apps like Waze™ and Google Maps™ help you get around using your phone's location services feature. But if these apps are running behind the scenes and you aren't traveling, location services can drain your battery.

Is it bad to leave location services on?

You'll use more power turning it on and off than just leaving it on all the time. There is no point in keeping your GPS on if you aren't using any app that utilizes it. But even on the other end, having the GPS turned on won't drain your battery if no app is actually using it.