Infrastructure

Telephone
In most lodges and cities you can find landlines. If you are using a mobile phone, you have coverage in all major cities and at all the mainroads.
In Etosha, your mobile phone will only work within the NWR parks (Namutoni, Okaukuejo en Halali). In Sossusvlei your mobile phone will only work in and around Sesriem.

Watersupply
Windhoek and some other major cities have an adequate watersupply network. In Windhoek a lot of chemicals are used to keep the water clean. There are tourists who drink the water from the tap. But it is recommended to boil the water before you drink it, this can prevent some nasty experiences.

Transportation

Roads
The government of Namibia gives a lot of attention to the national roads. All major roads are tarmac. The B1, the main north - south highway is probably the busiest road in the country, but you won't find a lot of trafic still. Most tarmac roads have a speed limit of 120 km/h, unless the trafficsigns tell you an other story. On tarmac, you can reach 120, no problems with that, but look out for birds and baboons who sometimes stay on the road untill you almost run over them.
Most of the other roads in Namibia are sand or gravel. If you are not used to drive on sand and gravel, you need to pay extra attention while driving on sand and gravel. Your car will react completely different on sand than on tarmac, so be aware. Some sandroads look very well, but an accident is always near, sand and gravel roads often have stones and rocks lying in the middle of the road, if you hit one, you will definitly lose a tire. So don't speed on sand, definitly don't go faster than 80 km/h.
Also be aware for the roads near the coast, heavy fog is a common situation which can appear in just a few seconds.
But it is not only the road which can cause problems, next to most roads you will find lots of animals, from the earlier mentioned baboons till eliphants. Please don't drive at night, still a lot of accidents with animals happen during night time.

It is recommended to keep your speedlimit as mentioned on the trafficsigns. The Namibian Police is also using state of the art technologies (lasergun) to check the speed of passing cars.
The tickets won't cost you a lot of money, but it is a waste of time, in most cases you will need to go to the nearest police station, which will cost you a lot of time.

Car
All the main roads are well maintained. If you are only travelling on the main roads (also the roads near Sesriem), there is no need to use a 4x4. Bur there are advantages of a 4x4, in Etosha you can probably spot the animals earlier on than driving a 2wd, and the comfort in a 4x4 will be higher, because some roads can be very bumpy for a 2wd.
If you are planning to go into the bush (Damaraland i.e.) you will definitly need a 4x4.
When you are travelling during the rainseason, it is wise to inform for the local road condition. Most rivers are out of water, except when it has rained the day before, a riverbed can change in a fast rapid, you don't want to cross such a rapid with a 2wd, so be aware.

Car rental
All major car rental companies are present in Namibia.
You can find all the car rental companies in Windhoek, Windhoek International Airport and some in Swakopmund and Walvisbaai.
For a 'normal' 2wd you will have to pay around 30 euro's per day.
For a 4x4 you will have to pay a lot more, starting around 70 euro's per day.

Bus:
The only public transport that is known in Namibia can be found in Windhoek, but still this is not the public transport which you will use as a tourist.
The only busservice you could use is Intercape. This is a South African company which provides transport between: Windhoek, Cape Town, Swakopmund, Walvisbaai, Runde, Katima Mulilo and the Victoria Falls. These coaches are really comfortable, but they need to be booked in advance.

Train
There are only a few railroad connections in Namibia, there is a north - south connection and a Connection from Windhoek to the coast. The trains are mostly used by the locals, you won't find a lot of tourists in the train. And don't be suprised if a train does not leave the station at the planned time, you need to be flexible while travelling with the train.

Air transport
The Internation Airport of Namibia is aproximatly 45 km to the east of Windhoek, just follow the B6 to Gobabis to reach the airport from Windhoek.
The major national airports can be found in: Katima Mulilo, Luderitz, Rundu, Swakopmund, Walvisbaai and Windhoek (Eros).
There are also some smaller (privat) airports in: Etosha, Sossusvlei and several lodges. There are several tour operators who can arrange a fly-in safari.