For most adults who are out of school, there's only one "grade" left that really matters in your life -- your credit score. A good one can save you hundreds of thousands of dollars over the course of your lifetime, and a poor one can in many ways prevent you from living the life you want to.

In this clip from Motley Fool Answers, Alison Southwick, Robert Brokamp, and Fool alumna Dayana Yochim answer a "length of credit history" question for a listener who wants to stop paying big annual fees for a rewards card she doesn't much need anymore -- but that's been active for decades. While you can take a hit to your credit when closing such an account, it's not fatal, and there may be good reasons to shed it, too.

A full transcript follows the video.

This podcast was recorded on July 12, 2016.

Alison Southwick: The next question comes from Sally. Sally writes: "I know that closing a credit card can be bad for your credit, especially if it's one that's been open for a long time and has a high limit -- the highest of all my cards." We're talking about a specific one now. "The issue is that this card charges $95 annually, and I don't use it that much, so it seems like a waste to pay the fee. It's an airline miles card. I don't fly airlines much anymore. I have other cards with better incentives, and I have adequate limits since I pay them in full each month. I do have one other card also opened in 1992. Should I take the credit reporting hit and ditch the card?"

Dayana Yochim: What's good to know is that the length of your credit history with a specific card like that is 15% of your overall FICO score, so it's not a huge amount there. More important is your payment history represents 35%, so, paying your bills on time. And another 30% is how much you owe compared to how much credit you have available to you. So closing that card won't necessarily be a complete disaster.

I would go the route of calling the credit card company to see if they can switch you to another type of plan within that card. Maybe it's just something straight up with no rewards and there's no annual fee for that. The other factor here is that she already has another card that's been open that long, so if a card is not working for you ...

Southwick: It's me, not you.

Yochim: Yes.

Southwick: If this relationship is not working for me anymore ...