I've had Chase Freedom Unlimited® (see rates and fees) for a few years now, and it's still one of my favorite credit cards in my wallet. Imagine my surprise, then, when I got an email from Chase telling me my credit limit had just gone up by a lot.

No phone calls. No forms. Just a more-than-40% increase -- from $9,300 to $13,100 -- all because I've used my card regularly and always paid on time.

Here's what to know about my automatic limit increase -- and how you can earn the same.

I've been using this card for years

I've been racking up cash back on the Chase Freedom Unlimited® for a couple of years now, and it's still a regular in my card rotation.

Cut to a few weeks ago, when I got an out-of-the-blue email from Chase, congratulating me and telling me my credit limit had just jumped almost $4,000 without me even asking.

It's a good lesson about the value of a strong credit history: Sometimes you can get rewarded just for staying on top of your debt.

Want to join me? Learn all the details of the Chase Freedom Unlimited® in our full review.

How to earn a credit limit increase

Plenty of issuers, including Chase, will automatically raise your limit if they see you're a responsible borrower. You don't need to wait for your card issuer to make the first move, though.

Using your credit card often, keeping your balance low, and never missing payments can all signal that you're a good candidate for a higher credit line.

These tips can help you qualify for a higher limit, either automatically or by request:

• Pay on time every month. Payment history is the most important part of your credit score.
• Use your card consistently. Card issuers like to see that you use your credit regularly.
• Keep your balance low, though. Keep your balance at less than 30% of your current limit, and ideally less than 10%. This is called your credit utilization ratio, and it's a big part of calculating creditworthiness.
• Keep your income updated. Higher income can support a higher credit limit.

You should probably be doing all of these things anyway, as these will also help you attain (or maintain) a high credit score.

Otherwise, a quick request might be all it takes. Many issuers let you request one online, though it may require a soft or hard inquiry on your credit report.

Benefits of a higher credit limit

A high credit limit isn't just about bragging rights. It can have real financial perks, like:

• Improved credit utilization ratio. This ratio -- your current balance divided by your credit limit -- makes up a big part of your credit score. A higher limit lowers your ratio, which can boost your score.
• More flexibility. A higher limit gives you more breathing room in emergencies or for larger purchases.
• Better rewards potential. With more spending power, you can earn more rewards with your card, especially if you pay in full each month.

Want a card with a high credit limit and strong rewards? Check out our picks for the best high-limit credit cards available today.

You've got to earn your way to a higher limit

Chase didn't give me a higher limit because I asked for it -- they did it because they think I earned it (whether I prove them right is another matter). Either way, though, a responsible credit history will help show your issuer that they can give you a longer leash.

Use your card wisely, and your issuer might reward you for it.