As explained several times on the forum, even if you haven't personally changed hardware, it's possible that some operations like updating drivers or flashing bios might appear AS IF you changed hardware. Just to make it clear, we don't do ANY hardware detection. Some of your drivers reported a different hardware id to Windows. Windows reported a new hardware id to the Esellerate engine, and our program simply trusted that this was the case.
But the system (not our system, but Esellerate's combination of the software+servers) IS able to recognize if it was really a new hardware or if it was just an update so, it's not always sure you "consumed" an activation.
But even if an activation was consumed, this wouldn't be a problem anyway because, there are 6 available exactly for this reason: sometimes there might be hardware changes detected with no apparent reason, but due to driver quirks/issues. And of course, don't forget that, even if you HAVE consumed all your 6 activations, a new one will be granted anyway if the last one was obtained more than 90 days earlier.
And, when you ARE planning an hardware update, it's best you always use the Deactivate function of the Addon Manager, to reclaim an activation. Ideally, if you always use the Deactivate function, your used activations count would always be 1, and you could do unlimited hardware changes. The 5 extra activations should be considered just as a safety against drivers quirks/issues that caused hardware change detections.