Evo wrote:

So what your saying is coped cuts don't expand and contract with the change
of weather?

Of course not. Coped joints hide the movement better.

I do both, mostly these days MDF painted white, that is the
style for now at this time. The only time I use a coped cut on crown is in
a bathroom with solid wood. The humidity changes are extreme. I live in
Southern California and the humidity changes are slight even while it's
raining.

I live in New England, where we get some summer humidity and dry, cold
winters.

I don't use caulk or glue except when I do a splice on long pieces, no need
too. Sorry to disappoint you when it comes to copes but I just don't see
them as necessary anymore at least where I live. I have seen my miters
years later when folks have called me back to do other rooms and they look
as good as the day I put them up.

I didn't see any location reference in the original post. Your corners
wouldn't look so good later in many other places.

Barry