It depends on your operating system and your MATLAB release, but Plausibly Yes you need a new license file if your MAC address changed,or if your boot drive changed.
The details of how it decides what to license against changed a couple of releases ago (possibly as early as R2014a). There was an update on one of the Mathworks Support items posted here last week. I was convinced that the update was incorrect so I did some testing, but in the time spent I could not prove the update was wrong (but it sure looked like it was wrong for Linux, and probably wrong for OS X)
