The subject line of this post is one of the most common questions I receive from people intrigued in my travel hacking. If you pay off your credit charges in full, then you are the only type of financial candidate to whom I would recommend my methods. Given that you are an exceptionally responsible credit card holder, your credit score is already high. I estimate that each credit card application affects your score by no more than a couple of points.
The impact of multiple credit card applications throughout the year will have a minimal effect on the rest of your financial portfolio. After all, we are not changing your actual spending volume. We are merely optimizing it by shifting your existing spending toward higher yielding assets, if you will. When you consider a worthwhile credit card could yield $700 of immediate value, you should not stress over the credit score aspect at all.
My current credit score is 15 points below my all-time peak, which is acceptable and may not even be related to the many credit card applications I have filed. In the end, your actual record of repaying your balances for your car, credit card, home, and student loans will impact your score far more than the act of applying for a new credit card.