As a volunteer for Friends, one would think that it would be ingrained on me to always go to smile.amazon.com when ordering something from Amazon.com. But I must admit, when in a hurry to order that rubber ducky, I sometimes forget, only to realize a day or so later, and much too late, my mistake. Hey, its only 0.5%, but of course those pennies do add up.
Fortunately for me, and maybe you as well, Chrome users can install the Smile Always add-on, which will automatically redirect any Amazon.com link to its Smile version. Firefox users have an equivalent Smile Redirect add-on.