Credit stacking mistakes — what did you learn the hard way?

We talk a lot about what to do right in credit stacking. But I think there's more value in talking about what goes wrong.

I've made my share of mistakes — applying too fast, not timing utilization correctly, closing cards I wished I hadn't. Each one taught me something that shaped how I approach stacking now.

What about you? What's the one mistake you made early on that you wish someone had warned you about? What did it cost you, and what did you change because of it?

Would love to hear the lessons people learned the hard way. That's where the real strategy insights are.