There are different levels of removal. Just taking out the forward sideplate screw and removing the crane and cylinder will give you plenty of access for cleaning. I do this fairly frequently when cleaning residue off the front cylinder face. I admit it isn't strictly necessary, but it gives me a little better access to the nooks and crannies. I don't take the ejector rod off a S&W revolver unless I believe there is something wrong there that needs to be addressed. All I usually do is confirm it hasn't loosened.
I take Ruger DAs apart more routinely, though again I leave the ejector rod in place.
I really leave the ejector rod alone on Colt DA revolvers I've owned. I sold my Army Special some years ago, but I seem to recall the threaded end of the rod was factory staked to the ejector.