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FAA AC120-74 Section 8.
The first attempt at new Qantas SOPs for lights reflected this document fairly closely. However, after many comments by line crew about multiple switchings required at critical times the policy was revised.
In the context of this thread the "Wing Lights" (name may vary according to aircraft type) were originally only required on lining up. The revised policy requires them all times during taxi up to 10,000ft and vice versa on descent.
Personally, when on final approach I have found the increased visibility of aircraft on/entering runways with wing lights on quite marked.