In general, I have found the optimal number of cards is between two and four. I like to see women have a primary credit card and a backup. I use an American Express card as my primary and a Chase Visa as my personal backup for places that don’t take American Express. For women who are working for firms where they have expenses that get reimbursed, I recommend a third card that is only used for work purposes to keep the accounting clear. For women who are running their own businesses I recommend duplicating the setup on the personal side, with one primary and one backup card.
But let’s talk for a moment about why you would want a credit card in the first place. Responsibly using credit cards helps establish your credit history (as well as provides the convenience of not having to walk around with wads of cash). In the current environment, if you ever expect to borrow money down the road, rent an apartment or even apply for certain types of jobs, your credit score may be checked. And believe it or not, responsibly using credit cards helps improve your credit history.
What does responsible use mean? Things have changed a bit since the 2008 credit crisis. Today, credit scorers want to see regular usage. So it helps to charge something once a month. It doesn’t have to be a big item, and let it be something you are planning on buying anyway. Then pay the credit card bill off on time and in full (use auto-pay if you are worried about missing the due date). One late credit card payment can knock off up to 100 points from your credit score.