You can install and activate SubLab on up to 3 machines at one time.
If you purchased SubLab directly from FAW, or you have already registered your SubLab license, then you can see how many machines you currently have activated inside your account.
Login here and then click on the Activation Codes tab to view your activation slots:

If there are more Machine ID slots filled than expected - do not fret!
When you update your OS, reformat your computer, restore from backup, etc., your computer will make a new Machine ID which can take an additional slot. It's normal and you can message support anytime you need your code reset 🙂