Buy low, sell high.

There is never a sure thing in anything. But if you don't save now it's pretty sure that you won't have much when you retire.

Also, the Dow is at all time highs right now. It's actually not a great time to invest but that's the way it is. Buying more when the market is down is best but we just put in our contributions and hope for the best.

And paying compound interest is how banks make their money. There's a reason they're so filthy rich. Everyone is up to their eyeballs in debt.