From Travel Strategies
It is difficult to collect the signup bonus a 2nd time, because of the Chase 5/24 rule. Normally, you are eligible for a Chase signup bonus, if you haven't already earned the bonus from the same card during the last two years. However, due to the Chase 5/24 rule, if you've been signing up for other cards, you won't be able to get approved when you reapply. You'll need get under the 5/24 limit before you can earn the bonus again. Dealing with the Chase 5/24 Rule.