I started with a 2AA Minimag in the 90s. Then found a 4AA florescent light from Radio Shack that was way brighter, but easier to damage and not waterproof. Then came the Princeton Tec 20 which was very waterproof, the bulb lasted longer than the mag, but runtime wasn't good enough. Around 2000, I started getting into l.e.d. lights when the first good ones came out. Among the first were the CC Expedition (7 l.e.d.), CC Trek light (2 l.e.d.), L.R.I. Photon II, Princeton Tec Matrix headlight, and Inova X5. When 3 watt luxeons came out, I spent $50 on the Gerber LX 3.0 which was the first one bright enough to night hike in the fog. I wanted more lumens for less money. I got excited when the 3 watt l.e.d. Maglites came out and bought a bunch since they were half the price of the Gerber light. Runtime stunk, and I wanted something that I could actually use for backpacking without having to carry pounds of spare batteries. I finally found the perfect light, the Fenix P3D Q5. It ran 16 hours on about a 50 lumen medium. I could hike all night long any time of the year without having to change the batteries until after sunrise. I could find the trail at a distance or signal for help with the 200 lumen turbo. I could go on night hikes in the fog or go trail running for extended periods of time without the batteries going dead with the 109 lumen high. I could also read or walk around camp at night without screwing up my night vision with the 5 lumen low that lasts over 70 hours. The P3D is the light that got me hooked. While I have more efficient lights today, I still use the P3D occasionally as the settings are perfect for my needs and the newer lights tend to have less throw. I have used it on backpacking trips as long as a week and on that week long trip, I never had to change the batteries once.