The major credit card issuers have various policies in place to crack down on those who apply for credit cards exclusively for welcome offers. While credit card issuers sometimes have big bonuses to get customers to apply, they do so with the hope of people holding onto a credit card long term. While it’s understandable that sometimes a card might not work out for someone, those who constantly open and close cards may find themselves facing some restrictions. In the case of American Express, the issuer has a policy of only letting cardmembers earn the welcome offer on a card “once in a lifetime” (this is one of several Amex rules, along with things like the five card limit ). Anecdotally, a “lifetime” in this context typically refers to a period of around seven years, though that policy isn’t published. So if you’ve had a card before, you won’t generally be eligible for the welcome offer on the card again.…