shielded vs unshielded pros and cons?

I read about this concerning ICs. Can someone help explain the  the differences to me and why it's important (or not),
WITHOUT BEING CONDESCENDING OR HIJACKING THE QUESTION? That would help me to understand it better.
Other than cost, there is no downside to shielded cables.
There are vendors on ebay who are small-scale makers of ICs, who claim sonic differences between shielded and unshielded versions of what is otherwise the same cable.
For ICs I go with shielded cables, especially when using long runs.

If the environment is free of EMI and RFI noise and the cables are short, unshielded cable should suffice. In theory shielding colors sound, so pick your poison.

I have no idea how you would measure how much EMI and RFI noise and determine whether it’s worth shielding or not.
As little as I can get away with, weaves help a lot.. Phono IC can get noisy. Being aware of placement.. and routing..  There are some noisy places inner city, what else you going to do.. The right shielding in the right place.. God sent..

Using shielded cables just to use them.. They can be kinda lifeless if you're not careful..

I use a brand of cables called Ocellia.  The owner offers both versions for his interconnect cables.  He believes that unshielded is the better sounding alternative.  However if your audio system is in an environment where RFI and/or EMI is an issue then he recommends shielded cables. 

I've used his unshielded Silver Reference for years with no problems. So scenario dependent.