The two licences mean that the software can be activated and used on two different computers at the same time. If a laptop breaks down, you can activate the licence on another computer, as the activations are managed flexibly and the oldest one is deleted in the event of a third activation. This means that you do not permanently lose a licence, but can reassign it as long as you have the activation key and an Internet connection. Deactivating on a defective device is ideal, but not absolutely necessary in order to use the licence on a new device.