I carried a Solitaire on my keyring for several years, but this light is now retired in favor of a Photon 2. LEDs rule. My most used light now is a Petzl Tikka. For heavier use (caving vs. just walking around at night) I use a a Petzl Duo with a LED in place of the original low beam bulb. My battery costs for lighting are now insignificant and I no longer need worry about spare bulbs.