I’m incredibly fortunate to have earned millions of miles with credit cards. The products and bank issuer policies — and best strategies — are constantly changing.

Here are 20 things you should know about signing up for rewards credit cards:

1. Chase’s 5/24 Guideline. In order to root out customers who just want to sign up for credit cards, pocket the bonus and move on, many people who have opened 5 or more new accounts within the previous 24 months don’t get approved for new Chase accounts.

2. Some cards are exempt from 5/24 mostly hotel cards other than the Marriott Rewards Premier Credit Card and non-travel/non-ultimate rewards cards.

3. There’s no hard limit to the number of Chase cards you can have or at least no known limit, limits are placed on approvals and total credit offered not on number of open accounts.

4. There’s no hard limit on frequency you can apply for Chase cards different people experience different things in terms of timing of getting more cards (eg no more than two cards in a 30 day period for some people, no more than one personal and one business card in 90 days).

5. You should get Chase cards first, then and other issuer business cards because most non-chase business cards don’t report to your personal credit. If starting from zero, your first several cards should be from Chase — Chase Sapphire Preferred, Ink Business Preferred Credit Card, then you’re free to get other bank business cards which won’t count towards ‘5/24’.

6. American Express allows only one signup bonus per lifetime per product.

7. A lifetime may or may not be 7 years. The once in a lifetime rule means as long as American Express remembers you’ve had a card, ask them what cards you’ve had to determine whether you’re eligible for a bonus.

8. Typically you’re limited to 4 charge cards and 4 credit cards from American Express, althoug some people have reported getting more.

9. There’s no limit to the number of American Express cards you can be approved for in a day in my understanding though I wouldn’t apply for more than 2 (and the second one is likely not to be approved immediately).

10. Charge cards are easier to be approved for — and approved for higher limits — than credit cards. Charge cards you have to pay off your balance at the end of the month, credit cards you should pay off the balance but are permitted to revolve credit, pay interest. A bank has a harder time estimating not just your current circumstance but your likelihood of being able to pay off money in the future that it loans you now, so credit cards can be harder to get.

11. Citibank doesn’t have a hard limit on the number of their cards you can have though of course how much credit they’ll make available for each person will vary.

12. After you apply for one card they’ll consider another application from you 8 days later, but you can’t apply for more than 2 cards in 65 days.

13. Generally Citi will give you the bonus on a new card account if you haven’t opened or close a card in that product’s family in the past 24 months. Since I have the Citi® / AAdvantage® Executive World Elite™ Mastercard®, I’m not eligible for the signup bonus on the Citi® / AAdvantage® Platinum Select® World Elite™ Mastercard® even though I haven’t had the latter card for a couple of years.

14. Credit scores improve with more unused credit so opening up new cards, getting more credit, that you aren’t using can make your score go up.

15. Most business cards don’t report to your personal credit, so spending on those cards doesn’t depress your score.

16. Most people don’t need to obsess over their credit score or pulls of their credit report. The most important thing for a good credit score is paying your bills on time. You care most about your credit score when seeking significant credit for things like a residential mortgage.

    Getting a new card, or generally requesting credit (causing a ‘hard pull’ on your credit) will reduce your credit temporarily by a few points.

    However the people who worry about ‘wasting a pull’ are those who truly push the envelope most getting the maximum number of cards they possibly can. Even that’s far less of an issue than it used to be with the restrictions that issuers have put in place on approvals and bonuses, it’s far less common than it used to be for too many inquiries to be the binding constraint.

17. Credit cards don’t mean consumer debt, and you can be responsible with credit. In fact For the most part the availability of credit cards hasn’t increased consumer spending — it’s shifted how that spending is financed. We don’t use layaway or store credit as much any more, for instance. And high interest (even higher than credit cards!) personal loans are far less common than they used to be.

    The key is to be honest and reflective with yourself. You need to be meta-rational. The most important question isn’t whether your credit score is high enough to get credit, but how you’ll behave once you get it.

18. Try to retain credit even if you cancel a card. Chase frequently lets you move your available credit from one card (the one you’re going to get rid of before a fee hits) onto another card (that you’re keeping). American Express has offered the ability to move around your credit between cards as well.

19. Consider product changes instead of cancelling. Since Chase cards are harder to get approved for if you’ve opened several new accounts, I don’t want to cancel Chase cards — I want to product change to a no annual fee product (and then that’s an account I can product change to something else I want later without an approval.. or a signup bonus).

20. It doesn’t take as high a credit score to get approved as you think