Hello Salameh,
Generally, it's good to have same kernel level across the landscape.
It's good to start kernel upgrade from your sandbox (Since, it will be a copy of Production system).
Give a gap for a week before upgrading in Development system. During which you might come across problem which might not have dealt with level you have upgraded to.
It's always best to provide a week of gap before next upgrade (For Quality, Pre-Production and Production systems).
Publishing Annual Plan for Kernel Upgrade for your systems is good for every one in your organization.
Thanks & Regards,
Ananda Swaroop