If you're still not convinced, consider this: With a savings account paying 2% interest, you would have to save $300,000 before you would see $6,000 in additional income -- an amount that can come much more quickly from a promotion or annual raise that you earn as a result of additional education.

5. Rental Real Estate

When you use the bank's money to acquire rental properties, you're effectively building your net worth. Once you start renting out the properties, use the income to pay off the mortgages instead of dipping into your bank account. Your properties will gain equity; plus, their market value should increase over time.

If you're not ready to acquire properties solely on your own, but you have real estate savvy, you can get a group of investors to come up with the down payment with the understanding that you'll have a percentage of ownership in the property. And once you've successfully financed the rental property, you can negotiate a fee from the investors for its management.

6. Health

Having good health is a critical asset to building your net worth. It allows you to work more hours and be more productive without spending a bundle on medical appointments, treatments or surgeries. Invest in good health by eating well, exercising and visiting your doctor for regular checkups.

7. College Savings

Many parents assume ownership of a 529 college savings plan for their children, which increases their net worth until it's time to use the money for school. 529 plans grow tax-free and distributions are also tax-free as long as they are used for qualifying educational expenses.

The funds can also be transferred between beneficiaries without penalties or taxes. For example, funds could be divided between multiple siblings.

8. Maintain Your Home

Because your home is likely one of your largest assets, it makes sense to invest in maintaining it. Things like replacing your roof, maintaining your gutters and regularly servicing your HVAC system can get you a better return when it comes time to sell. On the other hand, neglecting your home can give potential buyers opportunities to use lack of maintenance as a way to negotiate a cheaper price, leaving you with less money in the end.

9. Investments

Investing can be a good income strategy, but it's not a sure thing. Take the time to research investments before you commit. You'll also need to have a clear understanding of when to buy and sell stocks.

If you're inexperienced in the stock market, you don't have to go it alone. Seek out advice from an investment advisor who help you pick the best stocks for your portfolio based on the type of risk you're comfortable assuming and the return you would like to earn.

10. Household Items

You might not consider a new refrigerator or laptop a way to boost your net worth but consider the big picture.

Just like when buying a vehicle, it pays to buy the best quality, longest-lasting products you can afford while also considering the rate at which these items depreciate. Constantly paying repair bills and replacing appliances can be a costly endeavor, but buying quality items boosts your net worth because it leaves more money in the bank. To determine which brands and models are the best investment, read reviews, compare products and find the best deals.

11. Private Lending

Being someone else's bank allows you to generate passive income that can boost your net worth. Private loans, notes and trust deeds are investments where you loan money to private individuals or entities in exchange for interest.

With these type of investments, you'll still receive a consistent rate of return regardless if the value of the underlying asset goes up or down -- which translates into funds you can choose to reinvest and gain more wealth.

To protect your interests, make sure you understand the ins and outs of a potential investment by considering consulting with a professional with extensive experience for advice, such as a broker, entity or regulated and properly licensed partner.

12. Collectibles

Collectibles can be more than just a hobby. They can serve as a boost to your net worth -- especially if you become an expert in a certain area. Areas to consider investing in are fine art, antiques or rare wine. But just because a collectible item was lucrative in the past -- think Elvis memorabilia and general World War II items -- doesn't mean it's still a good investment.

That's why it's important to educate yourself. Visit with reputable pawn shop and gallery owners, as well as other experts in the field to gain the knowledge you need to invest in collectibles that will add to your bottom line.

13. Permanent Life Insurance

Most people assume they can't access their life insurance unless something happens to them, but that isn't always true.

If you have a permanent life insurance policy -- such as a whole life, universal life or variable life policy -- the premiums you pay will grow tax-deferred. Once the policy has reached a certain cash value, you can access the funds tax-free. The accumulated cash, less any fees, counts as an asset that can increase your net worth.

If you're interested in getting permanent life insurance, consider working with an independent life insurance broker.

14. Vehicle

The car you drive can put a major dent in your residual income. Flashy sports cars and luxury automobiles are nice, but along with hefty monthly payments, they're also the most expensive to insure, according to Insure.com.

Get the most from your investment in a car by researching factors like reliability, safety features, maintenance expenses over time and the cost of insurance before making a purchase. If you're not sure where to start, you can use a car-buying service to make the process easier.

Buying a dependable vehicle that will hold its value for years after you pay it off can keep you from the expense of having to purchase a new vehicle every few years, which can decrease your net worth.

15. Income From an Extra Job

Choosing to take on a side hustle can earn you some extra cash. And as long as you save or invest the cash, you'll increase your net worth.

Consider doing jobs that pay enough to make them worth your time, such as finding and reselling items for a profit, house sitting, driving for Uber or Lyft, becoming a virtual assistant or writing resumes.

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Cynthia Measom contributed to the reporting for this article.

This article originally appeared on GOBankingRates.com: 15 Most Important Assets That Will Increase Your Net Worth