My two sets of Pyrex mixing bowls from the 70's. I have used these bowls more than I can shake a stick at. And I really don't know which size I use more...I just love them. About 12 years ago, I was washing the 2nd largest yellow bowl and dropped it in my porcelain sink. It broke, and I just stared at the 3 pieces it was now in, in horror. I simply just stood there, over the sink, like one of my best friends had died. It was like I was missing a finger...I know, it really wasn't that bad, but when you come to depend on something and it's gone, it really hurts. From that moment on, I hunted every antique store and mall I went into. But everything I saw for sale was for a complete set of 4, which I didn't need. This summer I was in the Tacoma historical district and went into an antique mall that was so cluttered, I nearly left. You really had to stare to see everything that the owner had for sale. Well, what do you know, there were single pieces of the Pyrex bowls for sale, and there was my 2nd largest yellow bowl. Gosh, I was so grateful to have the family back together. And every time I use that bowl in particular, I am extra careful when I wash it. These bowls have served me well!