This subject is covered often by posts on this site, but once again - octane is a rating of the quality of gasoline which resists pinging. Higher octane gas does not have more energy in it, and will not make your car run better, nor farther, nor with less maintenance. All it does is keep your car from pinging under load, such as when you mash the throttle or are going up a hill.
If your car runs great on 87 RON, stick with that. If it pings under load, switch to the higher grade. Why spend money on something that gives no benefit?......Andras