We turn them on through 10,000'. The point being to make yourself more visible in the terminal area.
This is mostly standard in the US, the lights are not used to improve the pilot's vision, duh, but as an anti-collision aid. It has been firmly established that aircraft with landing lights on are much easier to see, no matter the time of day or night.
This was confirmed by studies by NASA, The Flight Safety Foundation, United States Air Force and the FAA.
I turned on the landing lights on during the descent every aircraft I flew at 10,000 feet as long as I can remember, and that's a long time.
Also the lights are on for takeoff and turned off leaving 10,000 feet on the climb.