Why do you need a headlamp on a trek?

One question that we get asked often is why a headlamp is required when a mobile flash/handheld torch can serve the same purpose. 

The answer is simple: 

1) On a Himalayan trek, at that altitude, in that cold, you want to keep your hands in gloves and probably in your pocket, especially for an early morning summit push. You cannot do that when you have a mobile in your hand.

2) Secondly you want to keep your hands free. Maybe you are using a trek pole or you are scrambling on rocks, you need your hands free which is not possible if you are using a mobile or even a handheld torch.