[gaius]

Yes and no. Saving cash makes little sense in the current financial environment, once you have your rainy day fund of 3 months living expenses. Buy an apartment or a house and put the extra cash into overpayments, you can't retire after 15 years but you could own your home free and clear.

[AppSec]

Keeping it cash? No. Putting it in a 401K, IRA, or market based account certainly does have much greater benefits. And of course, once that grows you can most certainly retire after 15 years. Or at least be financially independent and choose your working environment.