Yep - if it's an expense I have to pay monthly anyway and might as well use one card for my expenses then pay it off every month and reap the rewards points/cash back.

That's a good callout, it does give the feeling of freedom. People have to know what credit means, and know how they will pay it.

I am pretty good at keeping a rough running tally in my head of how much I've spent, and so I can feel that I'm getting close to my limit. Big purchases too impact that a lot. However, I've worked with people who don't have a system, or don't have the ability to do that. Not knocking them, but you do need some ability to keep track of how much you've spent, either yourself or with a routing on checking your amounts.

I just have mine paying my phone bill each month

Starting with only autopaid non-flexible spending is a good bet, and there are credit cars that will de facto get you an ~3% discount on those categories just for using them.

Remember, all cash rewards / points systems exist to make you spend more money, though. Like the cards, they're designed to increase your spending. So it's the same advice -- only think hard about it for fixed costs.