The Short Answer: Probably Not
If you are planning to spend your entire vacation within the 23 wards of Tokyo (Shinjuku, Shibuya, Asakusa, Ginza), renting a car is a terrible idea. It will cost you more money, take more time, and cause infinitely more stress than simply taking the train.
The World's Best Public Transit
Tokyo's train and subway network is the envy of the world. Trains arrive exactly on time, every 3 to 5 minutes. You can cross the entire metropolis for a few dollars. Conversely, driving across Tokyo involves gridlock traffic, confusing elevated expressways, and endless red lights.
The Nightmare of Tokyo Parking
The biggest deterrent to driving in Tokyo is parking. Street parking is completely illegal. You must find a coin parking lot or an underground garage. Parking in central areas like Shibuya or Ginza can easily cost 1,500 to 2,000 JPY per hour, with no daily maximum cap. A day of shopping could cost you $50 just in parking fees.
The Shuto Expressway (Shutoko)
If you do drive in Tokyo, you will inevitably end up on the Shuto Expressway. This is a multi-level, elevated highway network that snakes between skyscrapers. It features terrifyingly short on-ramps with no merge lanes, sudden exits on the right side of the fast lane, and blind corners. It is not for the faint of heart.
When SHOULD You Rent a Car in Tokyo?
You should only rent a car in Tokyo if you are using it to leave Tokyo immediately. If you are picking up a car at Haneda or Narita Airport to drive directly to Mount Fuji, Hakuba, or Nikko, renting a car makes perfect sense.