All Image-Line software can be installed multiple times for your personal use, with some conditions. Please check this knowledge base article for details:
Can I install FL Studio on more than one PC (if I own a License)?
If you continue to own and control the original computer, it is not necessary to uninstall or deregister our software until you dispose of the device.
Use your 'Lifetime Free Updates' to unlock the latest FL Studio version. Check out the FL Studio help Foolproof update or relocation to learn how to update and move FL Studio from one computer to an other.
Image-Line Support Team