When I first read the title of this thread I though that someone was looking for a PhD specializing in Middle Ages (History). Nevertheless the discussion headed in this direction. It turns out that some of our current PhD students (dinosaurs) were actually born in the Middle Ages..... Now seriously, I think most people would get the most out of the PhD experience when they have reached certain intellectual maturity that in most cases takes place precisely when people reach that critical age. I don’t hold a PhD but I think I would get the most out of this experience now that I am 36 than back when I was 24 - 26. On top of that I think nowadays continuing education is key in this quickly changing world. What was taught in schools and universities 20 years ago often no longer applies or is no longer valid. I guess in business degrees this may be the norm...... Besides, the US Government seems to encourage its citizens to pursue (advanced) university degrees no matter how old the individuals are. When I was a student in the US (on campus) the ones who contributed the most to our classes discussions were actually older students returning to update their knowledge or getting their first degree. Where I live, governments think that by age 23 (when students finish their university education) you already KNOW EVERYTHING which I think it is simply preposterous. They don’t try to get students back in the classrooms after that age; there are almost not evening or weekend classes, and are very few options to pursue advanced degrees (in some fields like engineering it is just impossible). I guess this is one of the main reasons why the US is 10-20 years more advanced than the rest of the world. What I am trying to say is go for whatever educational goal you wish to pursue without rationalizing too much your decisions. Who cares about your age or cost/benefits analysis when many of those are simply intangible? After all, a PhD would provide you not only with an excellent education that will help you enormously to become an authority in a specific field but also will probably open unexpected ways for you to understand how to be a better individual, how to know yourself much deeply, how to get the best out of yourself and around you which is why we are here in the first place. I think (as a non holder) that a PhD is one of those things in which the process is probably way more important than the goal itself. Go for it.