Lens filters are a matter of personal preference. Some people love them, others prefer nothing in front of their lenses. One filter you should put on EVERY lens you take with you is a clear or a UV haze filter. Basically, these will keep the dust off your expensive lens glass. Outside of that, a lot of photographers take polarizers with them. The light in Africa lends itself to being polarized. With that said, there are a lot of photo editing software out there that can mimic a polarizer after the fact.