I have a 200 gallon tank on a trailer that I use for most of my diesel fuel, but before that, I bought several yellow fuel cans for diesel. At the time, they were a buck cheaper then the red ones. Don't know why that was, but since I already had some red ones, it was a no brainer to buy the yellow ones.
If I need a small amount of diesel, I drive less then half a mile to my gas station and pay full price for it there, and use the appropriate color can. I like to have at least five gallons of gasoline on hand for the lawn mower, four wheeler and weed eater. I always use my best red container for this, as it might sit there for a month or more.
When buying diesel, I tend to buy more then I really need, even at full price. I can get red died farm diesel for less, but it's a ten mile drive each way. Time and fuel to get ten gallons of diesel doesn't make it worthwhile. I usually use yellow for this, but might use both colors, and save the yellow cans for last in case I fill up and don't use all of the fuel in the containers.
Right now, I have a red can sitting next to my lawn mower full of gasoline and an almost full yellow can next to my backhoe, which is already full. My dad is here visiting and running the equipement, so it's important for us to know what is in what container. The idea of telling him that the red can has diesel in it is too risky. He might remember, or he might not. This way, I know that he will use the yellow container for the backhoe and not mix it up. At 70, he's pretty sharp, but he does tend to confuse small changes.
I also have a gasoline engine in my dump truck and will used both yellow and red cans to get fuel for it. I will empty the yellow cans into it first and then save the red ones. Again, this eliminates confusion when one of us fuels it up a few days or a week later.
Eddie