Have some fun with it and learn something in the process by conducting my Imbalanced System Test. Only run 1 speaker for 100 hours as though breaking it in again. Then, play them both. Suppposedly because the one is not broken in the sound should be off, skewed, unlistenable due to artifacts that differ between them. The center image should become shifted, the tonal balance not even, etc. It should be immediately obvious that something is wrong, not a "I thnk I hear something that is different," situation. If break in is a significant phenomenon there should be differences in tonality, dynamics, resolution, etc. - you know, the typical "huge" or "big" change that people claim happens.
Supposedly cables need to be broken in, too. So, you will be testing both purported break in of speakers and cables at the same time! Bonus, double test!
What you will find, imo, is that there will be no skewing, no divergence between the performance of the two speakers. Switch the speakers from R to L. Are major issues, problems moving across the sourndstage with the movement of the speakers? Is it like throwing a blanket over one speaker, or does it sound like before? I suspect you won't hear performance variances between them. Then you will have learned firsthand that the entire break in misnomer is a waste of time and that you should just play your gear. You will also learn how arrogant people are to think their hearing is more consistent than electronics. i.e. thinking that the sound changes over time and they can hear it.
You will have poroven to yourself how much nonsense there is in the audiophile community. I will not have cost you anything but a bit of time and effort. :)