Almost never, especially as an undergrad, for the following reasons. 1) Cambridge/Boston has decent public transportation system (as there are plenty of buses and trains that will take you around the city, we won’t discuss the myriad breakdowns and delays on this post) and 2) with the emergence of ride sharing (e.g. uber/lyft) car sharing (e.g. zipcar) systems, you have plenty of options. Last but certainly the biggest reason in my opinion, parking situation is absolutely horrible. Most students live on campus all four years (Harvard has a great housing system where freshmen are required to live on campus, and you are part of a vital community in your twelve upperclassmen houses) and there are very few garages around Cambridge, with exorbitant fees. Very few (I would estimate less than 5 students per year) who choose to live off campus may bring a car if they have a driveway or street parking, but you must deal with shoveling snow and staking out parking spots on the streets, and the ridiculous “taxachusetts” payments. Really not worth it.