This question is a subtype of "Why should I save any money, anyway?"
There are two basic answers. One is the utility function, as has been mentioned. The same dollar amount has different value for someone rich and for someone poor. If you expect that at some point in the future you will become more poor than you are now (because your income stream dries up), it makes sense to transfer some money from the rich now-you to the poor future-you. That transfer is known as saving.
Answer two is risk management. Future in uncertain, generally speaking you would like to be able to handle a variety of unfortunate events. Money really helps with that. If you have no savings, you have no tools to deal with what economists would call "negative shocks" and that is likely to send you down a financial death spiral. Speaking technically, the costs of not having a reserve of cash on hand to deal with emergencies can be very high.
There is a variety of other answers (e.g. future might provide much better utility for your dollar so you want to save up for that better utility), but I think that the two above are the main ones.
(e.g. future might provide much better utility for your dollar so you want to save up for that better utility)
This is one of my main reasons for saving a lot and I'm surprised nobody else has mentioned it. If technological progress continues, it seems likely there will be all kinds of cool toys and useful procedures (e.g., cognitive enhancement or life extension) that one could buy in the future, not to mention investment and charitable opportunities, and I'd hate to be left out because I had already spent my money on a bigger house or flashier cars and clothes.
I know I said I'd be gone... but this was just a comment originally, and I noticed it may actually be relevant.
Elharo said in Munchkin Ideas:
I'm interested in the following:
Why should people invest in retirement? Or, instead, why should someone invest as much as most do in retirement.
Few facts that make it a boggling question for me:
You are 10% to 20% likely to die before you enjoy even your first retirement year.
People adjust much more to harsh economical conditions than they believe they would. They remain happy, as many studies by Seligman and others show.
People who retire are only happier as retirees if they retired by choice (I lost the paper, sorry).
Most people here live in rich countries - darn, hate to be the exception! - , and their state would happily provide them with at least the maximal retirement plan legal in my country (aprox 2000 dollars/month). And surely would provide them with double the minimal (about 200/month) if they needed.
If you have descendants, they may support you in case you are still alive, and if you are not rich enough to keep a house, you have a good excuse to be in company of loved ones (you have nowhere else to go).
Last, but not least: That person is not even you that much anyway.
Given all that, I have no clue what the whole fuss about retirement plans, and being 60% of a rich old person with a crappy body is all about, specially if you are in the grave.
I mean, in the cryopreservation chamber, of course.
Edit: A related question not worth its own post, but maybe worth discussing, is Should inheritance "jump" a generation. Everyone inheriting from grandparents, instead of parents? Just the abstract ethical question. Regardless of implementation procedure.