Its an irony that reformatting is easier, yet not as necessary. I only reformat when I want to change my drive partitions, or upgrade a hard drive, or sell the computer.
Reformatting on windows involves downloading your drivers beforehand, or saving the internet drivers to a flash drive and then downloading them after the OS install. With OS X, all of the drivers are already there. Thats a distinct advantage of Apple controlling the hardware, they know what drivers to include. Windows can run on so many configurations, that while its a great thing for customizability, its hinders reformatting.