When I was younger, I used to want to live forever.  I am guessing my opinion is changing since I used to work at the Oncology/Hospice department.  As we get older, you may be able to prolong life and even make a variety of body parts replaced but we still haven't been able to define the limit of memory or even retaining valuable memories in the older stages of life.  A few mind puzzles, a healthy diet, but how long can we keep up a routine before we realize it's too much for us to handle?  Even if we have a different personality, there seems to be generation gap to what we are used to things in our lives like experiencing a mom and pop stores and even indoor malls.  If there was an option to die at the end of the life cycle and eventually over time come back, I might take it.  However, to live forever while others around me may not be able to afford to live forever will be difficult with trying to relate to the changes in my own environment.  If we can rejuvenate our youth, we still will feel old with the capacity of memories we hold in the mind that eventually can easily want to forget what was lost or dear to us.  This is a subjective opinion about choosing to live forever and it is one of those ideas many will have a different idea during the different phases of their life cycle or events in their own situation.