I measure every bite that goes into my mouth, either by weighing or with measuring cups or spoons. I have an old (25 years old?) food scale that is not digital so it is not all that precise, but I always round up. I put everything into FitDay and I want to know exactly how much of everything I eat. I am a frequent overeater and grazer, and one of the ways I avoid these behaviors is portioning out everything I eat. Even salad and veggies!
Nope, I don't weigh lettuce, I don't weigh onions, and stuff like that. I don't weigh whole fruit like an apple or orange but if I'm tossing some stuff in for a smoothie I might weigh it. I weigh meat/poultry and seafood when I buy it and freeze that stuff in portions. Of course I measure when hooking up a recipe.
I just can't get into making myself into some obsessive, crazy, dieting person weighing a every piece of lettuce. Now, I'm not hating on people that do that. I just can't do it. Personally, that would be a recipe for me to quit.