NEW YORK ( MainStreet) — Ah, credit scores. They can be the source of so much stress. Many people avoid them until they need them—and at that point it's too late to make any changes. If your credit score is lower than you'd like it to be, consider the financial implications of ignoring it.

Let's say you want to buy a new home and you need a mortgage loan of $200,000. If you take the time to improve your score by 100 points before getting the loan, you'll save over $25,000 in interest. Even if it takes five hours to fix your score, that's like getting paid an hourly rate of $5,000 for your time. Pretty compelling if you ask me.

According to FICO, the number one factor in calculating your credit score is your payment history. Making even one late payment can drop your score by over 100 points. In fact, it's almost as bad as if you foreclosed on your home. Creditors are not messing around when it comes to getting paid.

But look, life is busy. Anyone can accidentally miss a payment once in a while. If that's ever happened to you, there's no reason to live with a less than excellent credit score. By taking action you can improve your score by 100 points in less than 90 days. Here's what you need to know.

First, find out what your credit score is. You can easily do this for free at CreditKarma.com or CreditSesame.com.

Next, pull your full credit report. You can get a free copy from all three credit bureaus once a year from AnnualCreditReport.com.

Once you have your full report, comb through it to identify which lenders are reporting a late payment to the credit bureaus. Their contact information should be clearly listed there as well.

If you have one or two late payments, you can ask your creditor for something called a goodwill adjustment. Creditors are not obligated to do this, but if you go about it the right way you can usually get them to remove the negative marks.

Being polite and persistent are the keys to scoring a goodwill adjustment. Call your lender to discuss your payment history, and briefly explain the cause of the missed payment. Ask if they'd be willing to stop reporting it as a courtesy to you. If the customer service representative is not able or willing to make the change, you can politely ask to speak to a supervisor, although sometimes it's best to mail a letter instead. Writing a letter is simple, and there are plenty of free templates available online.

Once your creditor approves the goodwill adjustment, it can take up to 3 months for the change to be reflected in your credit score.