Nairobi's bases are decided by traffic, not distance: the safari suburbs are half an hour from the animals and an hour and a half from a bar, and the nightlife quarter is the other way round.
Westlands — the going-out quarter
The densest concentration of bars, rooftops, restaurants and mid-range hotels in the city, around Parklands Road and Waiyaki Way. Best if your trip is about eating and music, and you are happy to make a long run out to Karen for the wildlife. Take a registered taxi or a ride app home rather than walking.
Karen and Lang'ata — next to the animals
Leafy, low-rise and expensive, with the Giraffe Centre, the Sheldrick nursery, Bomas and the national park gates all within a few kilometres. Ideal for an early game drive and hopeless without a car; a night out in town is a 45 to 90 minute round trip depending on the hour.
Kilimani and Lavington — the middle ground
Apartment blocks, guesthouses and a good spread of restaurants between the city centre and Westlands, with Lavington quieter and greener. This is where most mid-priced serviced flats are, and it puts you within reach of both ends of the city without paying Karen prices.
Budget by the commute, not the map
Nairobi traffic routinely turns a ten-kilometre trip into an hour, and it is worst between 07:00 and 09:30 and 16:30 and 19:30. Pick one side of town per day, book the Sheldrick and park visits for early morning, and treat anything that crosses the city at rush hour as a write-off.