Young people are missing an important aspect of saving that could help them retire rich

Saving money is a difficult habit to adopt when you're young. Retirement is decades away, and there's so much temptation to spend frivolously right now. And despite concerns about saving enough, many young people hold the misconception that starting to save money before they reach their 30s won't make much of a difference.

But the earlier you start saving, and the more consistently you do it, the more likely you are to become a millionaire later in life, says Farnoosh Torabi, a financial planner, author, and host of the "So Money" podcast, on a recent episode of Sophia Amoruso's Girlboss Radio.

"People get overwhelmed [when] they think about how much they'll need one day," she said. "The truth is that it's not how much you save when you're young, it's the frequency of saving when you're young … it's the consistency."

Torabi suggests starting small, because with compound interest - which she calls the "eighth wonder of the world" - any money you save will grow exponentially over time.

She says: "If you start at 25, saving $9 a day, saved over the course of 32 years - historically that has averaged 8% annual return - you can end up with $1 million by the time you're 67."

The simple fact that you'll end up with more money than you actually put away is one way to motivate yourself to save.

And though saving frequently is what will help you reach millionaire-status (if that's what you're after), Torabi offers another example to undermine the importance of starting to save while you're young. "If you're 25 and you start saving $10 a day today for the next 10 years, and then stop, and just let that money continue growing in those investments [until retirement], you'll have more money than someone who started at 35 and saved until retirement."

When it comes to actually putting the money away, Torabi's best advice is to automate your savings: "Just set it and forget it."

The important thing to remember is that the earlier you start - even if you're consistently putting away less than $10 a day - the more money you'll end up with.