NEW YORK (MainStreet) — It's a lot easier to kill your credit score than it is to build it up. In fact, your credit score can go from highly respectable to down in the dumps in as little as three months if you play your cards totally wrong. That won't just impact your ability to buy a home or a new car. It will also make it harder for you to get an apartment or even the job of your dreams. Building up your credit is the result of months and years of responsible behavior. Destroying it can happen quickly with just a couple of wreckless choices.

Ignoring Your Debts

If you have a debt you think isn’t yours, the absolute worst thing you can do is ignore it.

"It's pretty boneheaded to not pay attention to your statements," says Leslie Tayne, a debt consolidation attorney on Long Island.

She deals with people trying to get their financial house in order all the time, fighting old debts and trying to figure out how they’re going to pay off what they owe.

"People come to me, and they didn't realize they had these debts, because they stopped opening their mail," says Tayne, who adds that this is more common than people might think.

"Clients come in and dump their unopened mail on my desk all the time," she says. There's stress involved in being in debt and people -- quite incorrectly -- think that if they just bury their heads in the sand, the problem will go away.

Instead, Tayne says to get out in front of the problem. Keep track of your statements, call your creditors and try and reach a deal before things go into collection. Your credit rating will thank you.

Not Being Timely With Payments

It’s a fact: the biggest part of your credit score comes from how timely you are with making payments. And while a single 30-day late payment doesn't carry that much of a penalty, anything more than that, or a habit of making payments late is going to make your significantly less attractive to potential lenders.

"If you get a late payment, it will be reported pretty quickly," says John Heath, directing attorney with Lexington Law.

"A 30-day is considered a pretty minor infraction," he adds. "Once you get into 60 it becomes more serious. Anything over 90 days and you’re looking at it going into collections."

This is where things get really bad. Once a debt gets charged off, the impact on your credit is significant. It's not just about the late payment anymore. Now you have a second creditor who is going to come after you for the full amount, plus interest and fees. What’s more, you now have four bad marks on your credit report: A 30 day, a 60 day, a 90 day and a charge off that’s in collections.

Another reason to be timely with your payments? Heath points out that even after you make the payment, the fact that you paid it late will remain on your credit report for seven years. Tayne advises her clients to set up an auto debit from their bank account to make sure this is happening.

"If you're not doing this, you're playing with fire," she says.

Using Too Much Credit

You should carry an average debt utilization of 30% across all your cards. Still, it's a good idea to keep your overall debt utilization under 30% on each card.

"Each creditor wants to make sure they’re getting a responsible borrower," says Heath. This means credit reporting bureaus are interesting in identifying consumers who are using their credit cards to get by or maxing them out on a regular basis. Such consumers are a bad credit risk, so lenders don’t want to give them credit.

Similarly, Tayne says that in her experience there’s a problem with having too many credit cards at any given time.

"Having 23 cards is another bonehead move," says Tayne, who once had a client with just that many credit cards. None of them had a terribly high amount of debt on them, but together they totaled a whopping $20,000 in debt. It also increases the chance of making late payments or not even knowing which credit cards you have.

"I had a woman once who had cards she wasn’t even aware of anymore," says Tayne.

All of this boils down to one important piece of advice: Keep track of your credit. Know how much you have, where it is and when your payments are due. Otherwise, you’re, as Tayne quite bluntly puts, making bonehead moves and playing with fire.

--Written by Nicholas Pell for Main Street