As millennials age, they need to rethink their long-term investments

Millennials may still feel quite young, but in so many ways, we're adults. So it's time for our money management to grow up a bit, too.

In your 20s, setting up automatic transfers to high-yield savings accounts and starting your 401(k) are the biggest hurdles. But once you're into your 30s, you need to do more.

Make use of a higher credit score. Good credit can qualify you for better borrowing terms, so put that to work. For one, "in terms of bang for your buck, refinancing is an important thing you should be doing," said Priya Malani, founder and CEO of Stash Wealth, a financial advisory firm in Charlotte, N.C. "If you can move even a quarter of a percent on a really large mortgage, that's going to save you tens of thousands of dollars."

You also can get a better credit card deal. Consolidate higher interest cards. And if you've had success with the same card you've had since you were 21, you should consider instead a card that earns cash back or travel rewards. (But keep the old one and use it once in awhile to keep it active.)

Diversify your investments. Consider contributing more to your retirement account. You should be saving 10 to 15% of your pretax income. Next, plot out your intermediate-term goals for the next five to 15 years. Consider taxable brokerage accounts and 529s, to help fund early retirement, save for your child's education or plan for another large expense. Money for short-term goals (within five years or less) shouldn't be invested.

Plan for your next career move. Are you in the right job? Once you're financially stable, you can start thinking about whether you're in the right field or right job in your field. Also, are you positioned to make the amount of money that supports the lifestyle you want as you age?

Believe it or not, Shehara L. Wooten, certified financial planner and founder of Your Story Financial, a financial advisory firm in Dallas, said it's time to start thinking about retirement lifestyle, too, and how much money you need to save to get there.

Protect yourself and loved ones. What worked when you were 25 and single isn't going to cut it when you're 35 with two kids and a mortgage.

For one, Malani recommends a term life insurance plan if you own a home with someone else, have a co-signer on any loans or someone is dependent on you for support.

Second, you should consult with an estate attorney and other professionals about crafting a will, naming guardians for kids, medical power of attorney and how much money you will need to leave (and how to do that).

Besides life insurance, you may need tweaks to your retirement and other investment vehicles and may need accident or disability insurance.

Give to others. As your salary grows, it becomes easier to meet your needs and still have money left over each month. Some of that money can be budgeted toward meaningful causes. Estate planning can also help you map out how you'd like to donate money or valuable possessions to charity.