Spark condition
 

Does this spark seem to have been used for less than 8,000km?

My mechanic has charged me for sparks replacement without asking me, telling me they needed replacement. That happened a few months ago. Now, I took them out and this is how they look.

So, what is most reasonable? are they the ones I replaced 2,5 years ago, or could they be 5-6 months old?

From my limited understanding, I would say they are quite old and dead but I need to confirm.