It is true--sometimes I have to stop and think "what store am I in and what card do I use" when I am making a purchase.
First of all, I don't use any of the mileage cards beyond the initial need to get the bonus miles. That used to mean buy a cup of coffee. Recently AA and UA have both set the requirement that you must spend $250. Well, I suppose that helps them at least break even on an account-by-account basis. God love 'em.
Here's my method to my madness:
Costco: I use my American Express Platinum Cashback card. Tiers up to 1.5% and I get a bigger rebate with this than if I use the Costco card which is a flat 1%.
Restaurants: I use the Costco card. Give me 3% back. Better yet if I can use it at an Idine restaurant and bag 10 miles per $. Sometimes I can triple dip by using the
online entertainment book savers guide. When you can get all the planets to line up just right it feels like you are eating for free.
Gas/Supermarkets: I used to use the Citibank Dividend Visa. I had that card since 1993 when it paid 2% on everything. Over the years I have gotten almost 6K in rebates. Then they went to 1% and I stopped using it. Then they went to 5% on gas and supermarkets. So I started using it only there. Now they did away with that so I put it on the shelf. Recently I had applied for the American Express/Citibank Dividend card. That one is still getting 5% but I hear unofficially that will go away in December. I think I may have a Case card that does 5% for gas and groceries--I'll have to check that out before December.
AA tickets: I use the AA business Visa. Gives me 2 miles per $ on AA purchases.
In hotels (Hyatt, Hilton, SPG) I tend to use their card to get the point multiples and or signup bonuses for 1st, 2nd stay, etc.
When I fly (rent planes) I use the AOPA Visa. That, until recently, gave me 5% rebate on all aviation purchases. They changed it to something called "Worldpoints." I will probably close it.
For everything else--I currently have an ATT Visa that I had not used for years. They sent me an incentive to use it--5% on everything up to $300 rebate. So until I exhaust that I will use it everywhere the above cards do not apply.
When that goes away I will fall back on my Fidelity card that puts 2% into my kids 529 account. My poor kids have not gotten a dime for months.
I think that covers everything.