Credit cards can be a useful tool for younger borrowers. Used responsibly, they can help you build a credit history, make everyday purchases easier and give you some flexibility when cash flow is uneven. And for Gen Z and younger millennials, especially those just starting out in their careers, that can matter. Perhaps you are now trying to build financial independence while managing rent, student loans, car payments and higher costs brought about by geopolitical and economic fluctuations.But credit cards can also become expensive quickly. Just as it can build your credit score, it can also damage it if your…