It is worth noting that, like South Africa, none of the petrol stations in Namibia are self-service, nor do they take credit cards. 

Many of the larger petrol stations have ATMs on site, but in the more remote places, this facility may not be present (or the machine may be put of service), so you should always ensure that you have sufficient cash whenever you pull in to fill up with petrol.

Shell, Engen, Total and BP are the most common petrol stations, and the larger stations have shops selling drinks, snack food and magazines. 

When you pull into the petrol station, you will generally be waved to a free petrol pump by an enthusiastic attendant, complete with welcoming smile. 

As a matter of course, while the car is being filled up, they will clean your windscreen for you - and take great care in making sure even the smallest dirt mark is wiped away. 

If you are really lucky, they may clean all the other windows as well!

It is customary to tip around N$3 - N$5 to the petrol attendants who fill your car and wash the windscreen for you.  Funnily enough, you will often find that the total amount of petrol they put in the car means you will get enough loose change back for a tip!

You may wish to tip more if they check the oil, water and tyres as well (or if your car is exceptionally dirty!).  For this additional service, N$5 - N$8 is an acceptable tip.