The main differences between headlamps are the bulbs and the batteries.  Incandescent bulbs are bright to start with, but are known to burn out after forty burn hours.  LED bulbs are extremely bright and long-lasting.  Headlamp batteries are found on the back of the headlamp’s head strap on some headlamps and behind the bulb casing on others.  Climbers, bikers and runners who want the headlamp securing on their heads during activity prefer the battery pack on the back of the head strap.  In this style of headlamp, a third strap fits across the top of the head for stability.  Campers who want a headlamp for doing things around camp in the dark or general travel use prefer the battery pack inside the casing behind the bulbs.  This headlamp is lighter and more comfortable to use when sitting up, leaning back and reading in a hotel bed. When choosing a battery to use with your headlamp, consider the differences between alkaline and lithium.  Alkaline batteries last a long time and are not expensive to purchase. Lithium batteries cost more, but work well in cold weather, last longer and are lighter in weight.  Rechargeable batteries can be used in headlamps.  Also consider a solar charger for the backcountry.  Headlamps have varying numbers of bulbs, beams and brightness settings.  Be  sure to consider how many of these features will suit your needs to choose the right headlamp for you use.