As long as you have the discipline to actually pay the thing off it's fine. Many people think, "oh I have 0% interest, I'll pay it off later" but never set aside the money to do so and end up accruing interest.

I never buy something on them I couldn't immediately pay off in full when I hit buy. I've bought things in excess of my checking balance, but that's because I had enough in savings (separate from my emergency fund), and my incoming paycheck would put my checking balance well above my credit card balance.

That’s more or less the right way.

Use credit cards for everything for an automatic minimum 2% discount on all purchases (in the form of cashback or rewards depending on how you value them, and more if you optimize category spending…I.e. you have a certain card you use for gas or groceries or eating out because that card has the best rewards for that category). Enjoy sign up bonuses if you can responsibly make the spend requirement. Always pay off statement balance and never close accounts (downgrade/product-change to free cards if the benefits aren’t more valuable than the annual fee).

And enjoy 0% offers but never slip on payment because that’s how they get you. If it’s not paid in full in time or a payment is late they will charge you backdated interest. 0% financing is free money if you can afford it (and can use it) at this inflation rate. I’d been on the fence about replacing my aging appliances but 0% for 24 mos made that a no-brainer. I could afford to have bought those appliances with cash (it’d sting but it’d be doable), but I’d much rather keep that few grand in a CD or bond or mutual fund and pay a 23rd of the balance every month, making me money instead of the bank.

That is pretty much the right way to do credit. Treat like debit and/or find a way to have 0% interest over a few months time to spread a big cost across multiple months where it becomes affordable.