I always assumed credit scores were an integral and historic part of the American financial system.
They were not, they are very recent,most of your parents didn’t have credit scores growing up, and as you can probably tell or at least intuit, it’s mostly just a b******* scheme for those with capital to accrue more capital by invading your privacy.
If your total utilization is greater than 10%, or if you have a high balance carried over multiple months, your score will decrease. It will be a few months after the balance is paid in full and you utilization is reduced to below 10% that your score will recover. Then you are stuck with that card because if you ever close it, you will take another hit.
Opening a credit account is a commitment and shouldn’t be done just to get an interest free period on an appliance. You will be hit with a hard inquiry when you open the card, and will be hit if you ever close the card. An interest free period is not really a great sign-on bonus anyway because if you take them up on that, you will see a temporary hit to your score.
If you spend thousands a year at Home Depot (like a contractor or handyman) then a Home Depot card makes sense. I spend a lot at Costco so the Costco card makes sense, also the Amazon prime card makes sense for me because I shop at Whole Foods a lot.
A credit card should be paid off in full soon after you make the purchase. Get your points / cash back / etc and never allow a balance to hit the statement. The real value of the card is in the points/cash back.