1. Buying too much or too little life insurance to cover your new family. If you have people who are dependent on your income, you'll want to make sure they're provided for if you die. Having trouble figuring out how much life insurance to buy? Use the Insure.com Life Insurance Needs Estimator Tool.

2. Depending on the group life insurance available at work. Group life insurance amounts are often inadequate to cover a family's needs, and aren't portable once you leave your job. Lock in your life insurance by buying your own policy.

3. Having the wrong beneficiaries named on existing policies. Is your first spouse still named as the beneficiary on your life insurance? Remember to update these policies as needed.

4. Not getting all available insurance discounts. Do you and your new spouse have auto insurance policies through separate insurers? You may be able to save money by moving to the same insurer, making you eligible for a multivehicle discount and, if you have home or renters insurance though the same company, a multiline discount.

5. Not understanding coordination of health insurance benefits. If you have health insurance but are also insured under your spouse's plan, you'll want to understand the "coordination of benefits" rules. These rules decide which plan will pay, and for what, when you file a claim.