8. Figuring you'll use your credit cards in an emergency.

Once again, it's easy to ignore the possibility of your car breaking down, a medical emergency, or losing your job, but these are all scenarios that could quickly become expensive realities.

According to troubling research from the Federal Reserve, nearly half of Americans wouldn't have enough money on hand to cover a $400 emergency.

Not setting aside money in an emergency fund could ultimately land you in debt or force you to borrow from a long-term savings account if an emergency does arise.

How to improve: Create an emergency fund as soon as possible.

The amount of savings you need is highly personal, so it isn't usually measured in terms of dollars; rather, it's months of living expenses that money could cover should you lose or quit your job. The general rule of thumb: Stash six months' worth of expenses in a high-yield savings or money market account, where you may earn more interest than in a traditional savings account, and it'll still be easily accessible.