From the moment you choose to pack any electrical appliance or techno gizmo, you should carry a 3-prong to 2-prong electrical adaptor in your kit…
That may seem futile, but it won’t the day you have to break the “ground” prong (the round one that stands in the middle of other 2 blades) of a 3-prong electrical and you’ll be secretly hoping it wouldn’t disrupt the proper functioning of the appliance. By then, you’ll fully realize how crucial that little thingy is!
Also, a kit of travel electric plug adaptors and an electric current converter is something that you shouldn’t neglect, especially if you carry along some fancy gadgets (tablet, smart phone, camera, laptops, etc.). In developing and poorer areas/countries, where backpackers like to go due to a low cost of living, the electrical current is not so steady/even and you wouldn’t want to fry your gizmos because they’re connected directly to the outlet that ends up with a surcharge. Best case scenario: the converter will handle the sudden burst of electricity and will even it out. Worst case, you will fry your converter and have better chances of sparing your stuff.
Most small appliances and techno gizmos (cell phones, tablets, camera battery charger, GPS, etc.) will do fine with a converter that goes to 50-60 watts that will cost them 5-10 $. Should you go camping or need high-wattage appliances (even the cheapest and smallest hairdryer will bust 1500 W and a 10$ toaster will most certainly go over 500 W!), then you will need to invest a little bit more (25$ approx.) to have a converter that has a wider wattage range.
Check out these maps and this Wikipedia page for more infos!