A good quality reliable (emphasis on reliable) headtorch is an essential item for trekking the Kokoda Trail. I therefore recommend that you stick with known reliable brands such as Petzl, Black Diamond or Princeton Tec because our trek leaders have lost count of the number of times they have been asked to try and fix and/or replace a cheaper headlamp during a trek. Fortunately we always carry a couple of spares but sometimes this is not enough.
The other advantage of purchasing a quality head torch is the opportunity to use it after you return – hands free reading at night, working on tricky items, walking/jogging at night, etc.
We also recommend that you bring a spare torch with you as well. You can get small hand-held torches that clip onto your backpack or belt. When you get into your tent at night you can clip it onto one of the straps inside the tent so that you know where to reach when you wake up for a pit-stop – or you can use it to find your head torch!
You can do your reseach on the quality brands online so you know what you are looking for before you walk into your camping store – or you can purchase them online and save yourself the trouble – you Google brands such as Petzl and Black Diamond.