If you are sharing the same computer with another user and you both want to use your own accounts on this computer, the best way to accomplish this would be by activating a USB drive for each of your accounts. This would allow you to insert both USB drives when you are working on the shared machine and have access to the plugins for which you own the licenses for. The same would apply to the other user and in this case there would be no need to activate both the computer and the individual USB drives.