Yes, a 4x4 is strongly recommended for driving in Namibia. Around 90% of the country's roads are gravel, and while you won't engage the 4x4 function on every route, the high ground clearance and all-terrain tyres make the drive noticeably more comfortable and far better suited to these surfaces. Smaller cars frequently pick up underbody damage on gravel roads, and that damage is not covered by any car rental company in Namibia. A properly equipped 4x4 protects both your trip and your peace of mind.