Unfortunately I don't think "one card" is a realistic thing to shoot for.
As others have said, you definitely want to spread your business with a few banks - across a few different card networks - so that when you travel, if anything goes pear-shaped, you have alternatives.
My strategy (for a few decades) has been two wallets - one with "infrequent cards" and my regular day-to-day wallet.
In the everyday wallet...
- 1 card for high-value rewards/privileges for travel (Amex Platinum)
- 1 card for high-value travel earnings and no foreign trans fees (CSR)
- 1 card for grocery/everyday (unfortunately, because of rotating rewards, I end up having to switch out quarterly which one earns the best...). Maybe a 2nd depending on how the rewards are working. These 2 will be BoA Cash Rewards, Amex BCE, Discover, Chase Freedom, or Sears MC
- 1 card for restaurants (same thing... have to rotate quarterly, or default to Uber Visa for 4%)
- 1 card for everything else (Citi DC, 2% back)
- ...and my Costco Visa which is for gas
and in the "pull out when needed" wallet...
- 1 card with a high limit, low APR to use for anything that I need a few months to revolve (BoA Visa, 6.49%... and when they offer good 0% BT offers on occasion, even better).
- Plus I do believe in store cards when they actually deliver great value, i.e. Target 5%, Lowes 5%, Home Depot deferred billing, Nordstrom 3%+ (depends on when they have double rewards days), Steinmart 4% (when they have double reward days), BBB/WorldMarket 5%, Amazon 5%, TJX Rewards 5%, etc... but I don't normally carry them
This works for me because I'm both a rewards freak and organized. My husband *HATES* the rotating cards, but appreciates that I get us back several thousand $s in rewards every year, so he puts up with having to have a "cheat sheet" to know when to use which card where 
@MJ-san wrote:Unfortunately I don't think "one card" is a realistic thing to shoot for.
As others have said, you definitely want to spread your business with a few banks - across a few different card networks - so that when you travel, if anything goes pear-shaped, you have alternatives.
My strategy (for a few decades) has been two wallets - one with "infrequent cards" and my regular day-to-day wallet.
In the everyday wallet...
- 1 card for high-value rewards/privileges for travel (Amex Platinum)
- 1 card for high-value travel earnings and no foreign trans fees (CSR)
- 1 card for grocery/everyday (unfortunately, because of rotating rewards, I end up having to switch out quarterly which one earns the best...). Maybe a 2nd depending on how the rewards are working. These 2 will be BoA Cash Rewards, Amex BCE, Discover, Chase Freedom, or Sears MC
- 1 card for restaurants (same thing... have to rotate quarterly, or default to Uber Visa for 4%)
- 1 card for everything else (Citi DC, 2% back)
- ...and my Costco Visa which is for gas
and in the "pull out when needed" wallet...
- 1 card with a high limit, low APR to use for anything that I need a few months to revolve (BoA Visa, 6.49%... and when they offer good 0% BT offers on occasion, even better).
- Plus I do believe in store cards when they actually deliver great value, i.e. Target 5%, Lowes 5%, Home Depot deferred billing, Nordstrom 3%+ (depends on when they have double rewards days), Steinmart 4% (when they have double reward days), BBB/WorldMarket 5%, Amazon 5%, TJX Rewards 5%, etc... but I don't normally carry them
This works for me because I'm both a rewards freak and organized. My husband *HATES* the rotating cards, but appreciates that I get us back several thousand $s in rewards every year, so he puts up with having to have a "cheat sheet" to know when to use which card where
Good things to think about for sure. I like how organized you keep things LOL. This is definitely a hypothetical—I’m not planning on going down to only one card
