The idea of a "personal flashlight" might sound odd, but when you consider the needs of folks who travel, the increasing number of blackouts, tornadoes, hurricanes, and other natural disasters, it becomes clear that one could be handy. Modern flashlights and power cells are so small and efficient that there's really no reason not to have a personal lighting appliance available to you at any time.

1. Decide whether you want a flashlight that can be with you at all times, in a pocket, purse or on a keyring, or a slightly larger one that would ride in the glove box of the car, a backpack, or perhaps in a belt holder at work.

2. Do you want a really bright flashlight that will burn out cells in a fairly short time (for outdoor use, signaling, etc.), or one suitable for illuminating smaller spaces with longer-lasting cells -- perhaps small enough to hold in your mouth as you work?

3. Decide how much you want to spend, then research what sizes and styles are available. There are many others on the web; just search for "flashlights." be leary of chinese lights with a large #'s of bulbs they may seame like they will be brighter but will have a poor beam.

4. Decide between incandescent bulbs and LEDs, standard batteries like AAA, AA, C and D cells and the more exotic lithium batteries. Consider availability and cost.

5. Go to a store with a good selection of flashlights and see what's available. Target and Wal-Mart have good selections, especially of the newer LED lights (the best choice for most general uses).

1. Flashlights with incandescent bulbs have more "throw" (range) than LEDs, due to the way they focus. They also tend to be a bit cheaper. However, the bulbs burn out after a few hours of use, and are prone to breakage (especially if dropped when burning). Incandescent lamps waste most of the battery's energy as heat, and use up batteries quickly. An hour or so of use from a set of batteries at full brightness is about all you can expect. Their light also grows more yellow as the batteries die, which makes them seem dimmer than they are.

2. LED's (Light Emitting Diodes) are well on the way to replacing incandescent bulbs for most applications that do not require extreme range or intense light. They are from five to ten times more efficient in terms of battery life, and are unbreakable. They also last for essentially a lifetime, with full-brightness life of 10,000 hours and up. The light to the left of the quarter has more than a thousand hours on its LED, and is still putting out light equivalent to when it was new. Compare it with the two brand-new lights on the right.

3. If you want a bright spotlight, you will have to settle for an incandescent bulb. Some lights come with LED's for close work, and high-powered Krypton bulbs for long distances. They tend to cost more than two specialized lights would cost combined, but may be the answer for motorists, campers, security and law enforcement personnel, and others who need versatility combined with a handy unit.

4. Battery life is determined by brightness and the size of the batteries. If small size is an issue -- as it naturally would be with a personal light -- LED's are clearly the way to go. Some LED lights will give ten hours of illumination from one AA cell. The small quarter-size keychain light on the left of the photo gives light suitable for changing a tire and similar tasks for about 2 hours, then diminishes slowly while still producing useable light for many hours thereafter. The two in the middle use single AA cells for about 10 hrs at maximum brightness. The one on the right requires 2 AAA's for a full 1/2 watt of power and a battery service life of five hours plus ($9.99 at Target, an amazing value!)

5. "Service life" of a flashlight is the length of time before the light diminishes to 50% of maximum. Because of the way the human eye functions, this is generally about the level at which the reduction becomes noticeable.

6. Also note that there are "wind-up" and "shake" flashlights on the market that require no batteries. These may be somewhat more expensive and/or harder to find. They are very reliable due to their independence from batteries, but tend to be less bright than battery-powered lights. They are especially useful in survival kits and similar applications. For some reason many of them aren't waterproof, so if you're going to use them on a boat, choose carefully. Some of them are from 7 to 12 inches long, however, so those hardly qualify as "personal" lights that you'd carry with you most of the time.

7. The waterproof caution applies to other lights, as well. Most have O rings to make them splashproof, but few are suitable for submersion on purpose unless specified by the maker.

8. Alkaline batteries are your best choice for all around use. Lithium cells, which have a 10-year shelf life and perform better at low temperatures may be the best choice for special uses, like the light that will roll to the back of the glove box and remain there until an emergency five years later. They may also be best for camping, and applications where cost is less an issue than reliability and output, as they tend to produce brighter light for longer. (On the other hand, unlike alkalines that taper off as they die, lithium cells tend to die more quickly when they finally decide to quit.)

9. Rechargeable NiMH cells may be useful for some purposes, if the lights are specifically designed to use them. They produce power at a high level for quite a long time, then die almost instantly. However, rechargeables lose their charge "on the shelf" after a few weeks, and should not be used for lights that are to be stored until needed.

10. Many LED lights operate on AAA and AA cells. These are easy to find, and spares don't take much room. AAA and AA lithium batteries are available for special uses.