If any of these habits seem familiar, now's the time to change 

  • The last quarter is here, and it's a good time to start your resolutions early.
  • Common bad habits include not taking advantage of rebates, impulse grocery purchases, reckless use of the Starbucks app and not reading the fine print.
A woman browses her cell phone. 
Westend61 | Westend61 | Getty Images
A woman browses her cell phone. 

You know you could do better, but you don't know where to start.

As we enter the last quarter of the year, it's time to turn things around.

During the year, you bought items with rebates – but never filled out the rebate forms. You splurged on impulse items at the grocery store. You signed up for trial services, promising to cancel them when the initial period ended – but you forgot. You fell victim to mobile payment apps, and not a week goes by without buying a barista coffee. You lost your cool at Costco and bought things in bulk you either didn't need or that expired before you could use them.

The top bad financial habit, according to Sean Kelly, a certified financial planner at PNC Wealth Management, is broader in scope: not having a budget or emergency fund.

One-quarter of Americans, or 55 million people, have nothing saved for an emergency. Only about a third of households have a monthly budget, according to a Gallup poll.

These two factors can have a daily impact on your money, because they give you a rudder to steer and an umbrella for unexpected expenses.

Call it the "Starbucks Effect," if you like. "All these small purchases on a daily basis can have a large impact down the road," Kelly said. Spending $10 on lunch may not seem like a huge sum. But if you do this four times a week, the cost really mounts up.

It's easier than ever to spend money unthinkingly, given Starbucks or Dunkin Donut apps designed to speed through the checkout line.

The good news is that the reverse is also true. Instead of making large changes all at once, start with something small and specific. "Stay on top of those expenses and start with something small," Kelly said.

These spending tweaks can add up in the right direction. "Delete the [coffee] app," he said. "Plan your meals better during the week or plan for that once-a-week treat."

Watch out for so-called deals that tell you that you have to spend in order to save. Some department stores offer you store bucks: Spend $50 and get $50 in future savings. "But if you only planned to spend $20, you've just spent more," Kelly said.

Whenever an expense comes up, have a plan. Without one, you'll invariably spend more, whether it's signing up for a free service you imagine you'll remember to cancel or a transferring your credit card balance to a zero-percent card with a fixed term.

Use a calendar (digital or paper, whichever works for you) to write down the date to cancel your free trial.

While you're deleting apps, you might consider adding some that can help manage and easily cancel subscriptions, like Trim or Truebill. (Trim does charge for cancellations that require a letter or a phone call.)

Calculate the monthly payment on your credit card balance to zero it out by the end of the interest-free period.

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"One of the biggest issues we see is people who take an 'I'll do it tomorrow' mentality," Kelly said. They put off making adjustments to their 401(k) contributions. Set a day on your calendar for a financial review, and use it to hold yourself accountable.

Set a goal of forcing yourself to read the fine print. "It comes back to zero percent finance options," Kelly said. "There might be a piece that says if you miss a payment they will start to charge interest, and you might be liable for previous deferred interest." That's an expense that would come on top of your previous missed payment costs.

"When you start making financial decisions, have a goal in mind," Kelly said. "Implement the goal with small steps – not at all at once – and realize you can start today."

The best way is to build up good financial habits with easy wins, such as cutting back on those weekly coffee indulgences. As the old saying goes, Kelly says, the easiest way to eat an elephant is one bite at a time.