Licenses are for individual computers. One license is for one computer, for a concrete one, not for only one. When you buy a perpetual license, the license code will only work for that computer, and if you have to buy a new computer your license will not be valid for that computer.
If you buy a yearly service, and you change your computer for any reason, you will be able to receive a new license code for your new computer but with the same expiring date.
