Almost every student at Yale owns their own laptop; it's very rare to find a student without their own computer. This is because students use their computers all the time to write papers, to access Classes V2, to find library resources, and to submit work. Laptops can be taken to class, the library, the coffee shop, or outside. Make sure to get a model that's light enough to drag around.
However, having your own computer at Yale isn't necessary. Computers are all over campus in labs, kiosks, libraries, and residential colleges. The only time it is hard to find an open computer is during finals week. Labs are also a great place to work when you need a quiet, focused environment.
Almost the entire Yale campus is covered by at least one wireless network. These cover the residential colleges, libraries, nearly every classroom, and areas around campus like bookstores and cafés. The Yale networks are reliable, very fast, and secure. The only places without wireless access are in some unrenovated buildings at the Med School and in some of the Old Campus buildings where the walls are too thick to allow for general wireless (high-speed ethernet is provided).
Information Technology Services (ITS) provides great support services, such as product recommendations, educational discounts, free software, and campus technology information. Student techs from the Student Technology Collaborative are also available at each residential college to help students with their tech problems, from connecting with the network to a frozen computer. Student techs are also available during the first weeks to help new students configure their computers and get connected to the networks.