I love the look and plan on sporting it a lot this Winter. I'm wondering though: are there any guidelines regarding the most flattering length?

I'm guessing it's a different length for (pencil) skirts and dresses? Does the cut of the cardigan play a role as well, i.e. different "rules" for boyfriend cardigans, cascading cardigans and cardigans with a rounded hem?

- I tried on one of my new cascading cardigans (length is the same in the front and the back) over a pencil skirt. It hit me just below my bottom and that seemed about the right length for this look.
Then I tried it over a sheath dress (hits me above knee) and that did not look right at all (the cardi ends about 5 inches above the back vent - it looked even stranger when I added leggings to the mix).

- Would you say that cardigans with a rounded hem look best with pants? Or could a skirt/dress work too, depending on the length of the cardi (mine seemed a bit long for this).
Example of cardi with rounded hem in case you don't know what I'm talking about:
http://www.shopbop.com/oversiz.....tid=affprg

- I feel like I will need an even longer cardigan to wear with knee-length dresses?