I put as much of my spending on credit cards as I can, to collect the cashback rewards.
I see a lot of credit card offers that have a signup bonus--I've taken advantage of several of these offers in the past. So to maximize rewards, I'd like to be open a new account (and possibly closing an existing account) every XX months to take advantage of these offers.
What is a reasonably safe number for XX to not adversely affect my credit score?
Edit based on comment
More info: I currently have 4 major credit card accounts, and I primarily use a single one that has the best rewards, but will use another that has better rewards in certain categories. I also e.g use Amex at Costco, since they don't take Visa.
I would imagine I would close one each time I open one, but really looking for the best way to do it (is it better to close one each time or leave them open?).
The newest one was probably opened 2-3 years ago.
I pay off completely every month, so probably never have more than 10% of my total credit limit on all cards combined.