You can’t own even one credit card.

A Credit Card can be used only by the person whose name is printed on the card. This is a cardinal, if not very well-known, rule of the credit card industry. Through my work in the credit card industry, I know that a credit card can’t be used even by other family members of the person to whom it’s issued i.e. it’s strictly non-transferable.

So, in effect, you’re merely renting / using a credit card. A credit card is always owned by the bank that issues it.

With that bit of housekeeping out of the way, IMO, you should definitely have 1, maybe 2 credit cards. Even a number of 3 is justified under under exceptional circumstances.

Back in 1985, a business trip to Eastern Madhya Pradesh (now Chattisgarh) got extended by a couple of days. The travel advance I’d taken (in cash) from my employer got depleted faster than I’d imagined. On my way back, I got into the AC 2 Tier coach of the train at Durg railway station. It was only after the train left the station that I realized that I was short of around INR 1000 required for the ticket back to the then Bombay. I looked around, saw one gentleman and shamelessly asked him for money. I saved the day with the loan I received from this Good Samaritan stranger co-traveller.

That was the day I realized the need for a credit card. I promptly applied for one when I got back home.

The first time that card got declined due to technical reasons, I realized the need for a standby credit card. I applied for one and got it around 1990.

From that day until today, I have diligently followed the 2-credit card policy.

Apart from serving as a standby, two or more credit cards offer a few advantages:

  1. You qualify for a higher line of credit, which can be very useful to meet medical emergencies.
  2. Silicon Valley folklore is full of stories of startups founded by entrepreneurs who raised seed capital of a couple of hundred thousand dollars by maxing out 10–15 credit cards.

But, of course, there are implications of having too many credit cards on credit score etc., so I’ll draw a line at max 2–3 credit cards, not more.