I fly regularly between LA and NYC and have the Delta SkyMiles Blue Card. I usually fly Delta but sometimes fly JetBlue or Alaska. I decided on Blue because I have the Platinum already and didn’t want to pay the addition annual fee for the Purple, plus the rewards with Platinum seem to be enough. Aside from my Platinum and Delta card, what other cards do people benefit from, either it be another Amex card or from a different institution alltogether? I’m based in NYC, but as I mentioned, I go to LA often, which is where I’m originally from. When I’m there I always rent a car and I love the insurance that the Platinum provides with my rentals.

Sorry if this seems like a dumb question. I just want to make sure my credit portfolio is diverse and I’m not missing anything that I could benefit from.

Also, I’ve been using my Platinum card for nearly all my purchases since I got it a few months ago and paying off the statement in full each month. I’ve used my Delta card for just booking Delta flights. Are there times when one is better to use than the other for certain types of purchases, or when using your platinum card is just not beneficial (assuming you’ve met spending requirements for introduction points)?