Ugh, I hit my 6K in annual grocery spend in 2017 and kept using my American Express Everyday Preferred Card.
Recall, you earn 3X Membership Rewards points per $1 spent at supermarkets.
HOWEVER, these 3X bonus points that you earn at supermarkets are on up to $6,000 per year in purchases. After you spend $6,000 in a given year, you only earn 1X Membership per $1 spent at supermarkets.
I usually am very good about keeping track (by calling Amex periodically) of my spend. When I hit the 6K I usually switch to another card that I would rather use to spend at supermarkets. This year that card would be my new American Express Blue Business Plus Credit Card, where I earn 2X Amex points on ALL purchases. I hit, the 6K back in July (really? ) and have only been earning 1X point on my grocery spend since. :-(. Bye Bye Amex Everyday Preferred for the remainder of year and Hello Amex Blue.