Rubber vibration dampeners - do they need replaced?

[dbcch]

Since DJI ships 4 replacement rubber vibration dampeners with the P2V, I couldn't help but wonder if they needed periodic replacement. Do they?

Yesterday, while installing a FlyTrex core, I went ahead and replaced them. The older ones seemed to be less stiff. Or maybe the second set were a stiffer set (unlikely).

Do they wear out over time? Is that why they shipped with a replacement set?

Thanks!