The simple question to your answer is look at your histogram. If the bands are often clumped at both edges, you need more dynamic range. If they're nicely packed in the middle you are doing fine.
Well, that's wrong. Histogram is just a light meter (sort of). You can't always get a nicely distributed bands, only if the light and the scene is optimal.
You don't understand what I meant by clumping. Clumping is what happens when you're either blowing the highlights or underexposing the shadows. Having greater dynamic range is the equivalent of stretching your histogram.
Not all pictures can give you evenly distributed bands, but that's not the point. The point is whether the entire scene can fit without blowing the top or bottoms out. And more dynamic range does this for you. Take a sunset for example, where getting the sun "yellow" without turning your foreground black is very tough on any camera. The histogram will show two peaks at each end. Now with more dynamic range, you get the peaks looking more spread out at each end. In an image, you will be able to make out more detail in the foreground without turning the sun white. It's all about understanding what the curves mean.
When you want a silhouette effect, however, less dynamic range can be your ally (since you want a perfect black but not too dark background). Thankfully, any camera can do it - you just need to raise ISO as that kills a camera's dynamic range.
Unfortunately I don't know whether Nikon 1 has live histogram yet, but this was one of the reasons I concluded that I needed a bigger sensor than APS-C.
Staring blindly at the histogram is pointless, but if that was your reason to get an FF camera than you made a big mistake... Olympus have always had live histogram and their cameras are smaller and cheaper than FF, and also have smaller sensor than APS-C.
Obviously composition and exposure are two very different aspects of photography, and no, I don't stare at my histogram when composing. Technology rarely helps you with composition (rule of thirds grids and horizon levels being about as good as it gets there), but it does help you with exposure. The question was "do I have enough dynamic range" and if you want an objective look at what is being over- or under- exposed, the numbers don't lie. And if you're having trouble and want to get to the bottom of "why", these are tools to explain it. Of course, people who aren't looking for truth but for self-affirmation will want to avoid objective measures, but those who want to improve may be interested in the real reasons behind one picture being less well-exposed than the other. If you see a well-exposed photo with rich color and tonal range you can double check a histogram and see that light is evenly distributed there as well. If you see a picture with obviously blown highlights or under-exposed shadows, check the histogram and you will see peaks at the respective ends. Now that you understand the reasons in the obvious, you now can transfer this knowledge to help you with the marginal cases. Take a look at some of the images shown already in this thread - several actually have marginally blown highlights (the cat in the window is the worst one). Now they are well-composed pictures, but they would be much better if they had been shot with a camera with better dynamic range. Basically, these
are cases where the photographer would actually get better pictures with a better sensor.
