Using a tent?
Whether to use a tent or to sleep in the open is a personal choice, dependent upon where you are. In an area where there are predators around (specifically lion and hyena) then you should use a tent – and sleep completely inside it, as a protruding leg may seem like a tasty take-away to a hungry hyena. This is especially true at organised campsites, where the local animals are so used to humans that they have lost much of their inherent fear of man.
Outside game areas, you will be fine sleeping in the open, or preferably under a mosquito net, with just the stars of the African sky above you. On the practical side, sleeping under a tree will reduce the morning dew that settles on your sleeping bag. If your vehicle has a large, flat roof then sleeping on this will provide you with peace of mind, and a star-filled outlook. (Hiring a vehicle with a built-in roof-tent would seem like a perfect solution, until you want to take a drive whilst leaving your camp intact.)