[csharpminor]

Yes, some people cannot afford to save for retirement. As the article mentions, you shouldn't invest money that you can't live with for at least 10 years.

However, the opportunity lost for every year you defer retirement contributions is huge, especially when you factor in the employer match you could be getting.

If you assume a $200 a month contribution at about a 3% rate of return, the difference between 39 and 40 years of contributions is $7,600. Discounting the $2400 in contributions you would have made, that's still $5,200 lost just for waiting a year. And we're not even factoring in an employer match.

Again, agree that for some this may be a tough decision. But generally speaking, if you receive a salary and have the option to participate in a retirement plan, you should do it.

[somic]

Participate in 401k plan - yes, 99% people would benefit from starting as early as possible. Max out your per-paycheck 401k contribution (including in order to maximize employer match) - not always. The farther you are from retirement age, the bigger your opportunity cost is going to be (your 401k money is locked-in into retirement account).

There are also certain 401k rules that may play very hard against you. For example, take a look at mandatory withdrawals ("required minimum distribution" - RMD) for some types of retirement accounts in the US at certain age + how your retirement account suffers disproportionately if market is down when you start mandatory withdrawals.

I know the math you are talking about, it does make sense conceptually and that's why it's cited in all 401k materials, real life with its rules and uncertainty is bit more complicated.