Forever. Such an interesting idea. How long does forever last? I would hazzard a guess that it lasts as long as we do.
Are we destined to be eternal? Physically no. Spiritually? Mentally? No one can honestly say such for a fact (some may believe with all their heart and that is truth enough you might say). If we are destined to be eternal, then forever has no meaning. If we do have a shelf life, so to speak, then forever is as long as we will be.