3-pin 13 amp plugs are the most common sockets. Depending on where you are coming from, some of these may not be an issue. Some places in Nigeria are not that safe. Always take precautions when traveling, and don't trust too easily. Not all roads are paved, especially when you start to get out of the cities.
Traffic can be a huge problem.
Once again, depending on where you are staying, there may not always be a constant supply of running water. This is not always in constant supply. If the place you are staying does not have an electric generator, there may be times that you will be without power. However, most places are equipped for this in terms of having an ample supply of candles, lanterns, etc. Phones are not readily available in all areas.