Cantabit vacuus coram latrone viator.
Travel light and you can sing in the robber's face.
What To Pack
Things that must be plugged in are in conspicuously short supply on my own personal packing list; they add bulk and weight rarely compensated for by usefulness. Try hard to eliminate them.
If, however, you just can't live without your electric shaver (a small bottle of shaving oil and a razor are much more appropriate), or your hair dryer (think about towel/air drying, or even a more travel-friendly hair style), don't forget that electrical power varies throughout the world.
Plug adapters and voltage converters are available for all of this, of course (Walkabout Travel Gear is a particularly well-equipped and helpful source of such devices); also check the "Destination" section of the TraveLinks page for an excellent information site). Remember that, when using converters, you must also be concerned with power (wattage) ratings. And some devices — often those with motors — are sensitive to the AC frequency, which cannot (in any practical manner) be converted.
Plug adapters can be found featuring all sorts of ingenious constructions, such as the "Tripshell Universal Travel Adapter" (pictured at left), which provides configurable plug adaptation for some 150 countries worldwide. It incorporates a 6A fuse (which means it will handle 660W @ 110V, 1440W @ 240V), L-N surge protector (to isolate sensitive electronics from potential power spikes), 110/230VAC voltage indicators, and child safety shutters. These can be a convenient solution if you're travelling to many parts of the world on a single trip, but for a modest number of destinations, simple single-solution adapters will be smaller, lighter, and considerably more reliable.
Many products (especially modern electronic devices such as computers, cameras, and cellphones) are available with "universal" power supplies or multi-voltage settings; you'll still need plug adapters, though. And remember: if you carry electrical devices that must be plugged in, you should be prepared for a shortage of available outlets (often in limited-supply/high-demand locations such as airports and hostels); consider bringing along a cube tap or the equivalent, to help both you and your fellow travellers.
If you choose to travel with a device having a 120/240V switch, get into the habit of switching it to 240V when you pack it: should you mistakenly plug it into a 240V socket when set to 120V, you will have an ex-device.
The various cables associated with electronic devices (some of which are considered in the Specialty Items section of the OneBag packing list) are notorious sources of unnecessary bulk and weight, and attract unwanted attention from security personnel. Companies like CableJive (one of their Apple cables is pictured at left) and Kurze Kabel are useful suppliers of short cables to help reduce this problem.
If you've become wedded to a smart phone or other portable device, and your travels take you to places where electrical outlets are in short — or nonexistent — supply (this can even include long flights and road trips), you need to think about carrying a spare battery, something more easily managed with some devices than others. One popular solution is the Anker® Astro series of portable, rechargeable power packs; their mid-range (10,000mAh) model (pictured here), capable of charging one or two USB-connected devices at up to a 3-ampere level, is a quite compact 5.6×2.83×0.55 inches (14.5×7.19×1.4cm), and weighs a not-too-intolerable 8.48 ounces (240g). Larger and smaller models are also available
A number of low-power electrical items, such as battery and cell-phone chargers, can be obtained in USB-powered versions, reducing the need to carry separate (heavy, bulky) converters. If you lug a laptop, you can plug them in there, though many modern televisions come with USB ports as well, so check the one in your hotel room. Alternatively, carry a small USB wall charger: I like PowerGen's excellent travel version, as pictured here; if you plan to charge two large devices simultaneously, the iClever charger will do so a bit faster, but at a cost in bulk and weight (both models have foldable plugs). Of course you can best eliminate the hassles by eliminating the gadgets.
Even if a hair dryer does make a great sock dryer.
Not necessarily; just be judicious. For example, a simple immersion heater is one appliance that many travellers (especially those on a limited budget, trying to avoid restaurant meals) consider invaluable. Place it in a cup of water, plug it in, and in almost no time you have boiling water. This not only kills all disease organisms, it also lets you make a hot cup of tea, coffee, cocoa, soup, noodles, etc. You can even cook an egg: bring the water to a boil, remove the heater, drop in the egg, and wait (ten minutes or so for hard-boiled, about half that for soft).
Small, lightweight immersion heaters — like the Franzus IH100 model pictured at left — are inexpensive and available in dual (120/240) voltages, though you may still need a plug adapter. Alternatively, you can buy such heaters locally in most developed countries.
You may read deprecating remarks about the reliability of such heaters, mostly from those who don't understand that they are designed to be plugged in only when the heating element is fully immersed in water. So make it a habit: immerse before plugging in, and unplug before removing. Always. Otherwise they can burn out in a flash (even the ones that claim to have built-in thermostatic shut-offs)!