If it is for me, I will open the pack and enjoy the tea. Put them in ziplock after opening them. If it is 15 years for Sheng, then it is really nice. If it is shu, it will start to go sour over the next few years, so finish it fast.
It is good to collect Puer and drink them occasionally to experience their changes over the years. For me, I will drink them no matter how old or new or expensive. It should be a simple enjoyment without all the noises of glamour or speculation.