There's another example where rules vary a bit globally--and even from state to state in the US. All of that would be incorrect in a US context. High but unused credit lines are almost always a help, not a hindrance in obtaining credit.
The thing is they will usually refuse to acknowledge that you have a long track history of paying off the credit card on time every month. You are actually better off having a debit card. And in fact we have just ditched our credit card in favour of a debit card for this very reason, it's one less thing they can hold against you when you apply for a loan.
No, I lived in the US for many years, having credit & using it to maintain a credit history was vital to getting a loan, renting an apartment, or buying a house.
Black Sheep is correct. I'm in the US. The whole credit-rating thing is completely weird and non-obvious. Having a large amount of "available credit" is considered a Good Thing by the data-miners like TransUnion. They like when you have "long term credit." That is: a credit card you got 20 years ago and you pay in full each month is excellent.
They don't like high usage-to-available-credit ratios. That is: if you have $10,000 available credit and you carry a balance of $5,000 a month, that's bad -- even if you pay the balance in full every month and never incur interest charges.
The hilarious thing is that it's actually quite easily for an adult to have $50,000 or more in available credit-card credit. If you carry a $5,000 monthly balance and pay it in full each month, then your usage ratio is low even though the balance might seem high and they like that.
So here in the US credit card usage history is one of the most significant parts of your "Credit Score" © ® ™ . Never cancel a credit card or close the account as that counts against you in the "time since opening the account" category. Just don't use the card. Put it in a drawer. Make a charge at a candy machine with the card once a year to keep the account active.
The absurdity: if you don't have credit cards you don't have a "credit usage history" and the dataminers use that against you. You're not credit worthy because you have never needed credit.
(I won't even get into how landlords and even employers will pull a credit report on potential lessees/hires. That's pure evil.)
On the gripping hand, all of the credit card issuers want your business because they want the swipe fees. They are willing to give "cash back" rebates on purchases. Of course those rebates come right out of the swipe fees merchants pay, and that comes right out of your pocket as the merchants add the cost of the swipe fees to the selling price of whatever you're buying. The point is that if you are disciplined enough to control your spending and ensure you pay balances in full each month, there's no benefit to paying in cash or with a debit card.
Credit-card issuers add more gravy on top -- extended warranties for purchases, insurance for rental cars, and of course the big one, which is the ability to start a charge back if a vendor is problematic.
As for debit cards linked to a checking or savings account: NEVER EVER EVER use them for purchases at point of sale in a store or online. EVER. Why? Because if the card is compromised, the Bad Guy can wipe out your checking account before you know it. Eventually you'll be made whole by the bank, but what happens if the account is cleared out then your mortgage payment hits? Bounce city, a mess to clear up, and guess what? Bouncing a mortgage payment is a nice big ding on your credit history.
anyway.