It really mostly becomes a matter of how each individual feels about it. Any authority that makes recommendations will always be super conservative, using a number of days that pretty much guarentees meat will still be good if refrigerated, eve poorly. As to the absolute time cooked meat will keep, it depends on the storage temperature and the amount of water left in the meat. I think most people just feel after four or five days that something about it just puts them off. So, except for mistakes, few people ever keep it around until it actually spoils. The same nose test that warns of off raw meat applies to cooked meat. And I suspect that cooked meats become objectionably smelly or moldy long before then could do any harm.
I would personally shrink from rare meat over three days old, strictly on a feels wrong basis. I wouldn't keep cooked fish that long, because it seems to just deteriorate aesthetically. I have often well roasted a big pack of chicken thighs on a Sunday and used them for lunches all week, and the last pieces have passed the sight and smell test for days longer. Beef cooked medium rare or better (or medium or better under some guides) has had the usual bacteria killed, so it starts new at that point. Rapid cooling and storage maximizes the time before it become unpalatable from bacteria growth, and it would likely become unpleasantly moldy first. I have forgotten medium well beef in the refrigerator for two weeks or more without it being objectionable, other than the time would put me off. I don't doubt it was safe enough. Of course, there are limits, as our break room fridge science fair experiments demonstrate.
My feeling about fried chicken would be that, long before the meat was bad, the breading would be kind of deteriorated and not really recoverable. Old pasty sodden crust wouldn't appeal. My expectations for five day old fried chicken wouldn't be high.
In fact, whole cuts of meat, in advanced countries, are very rarely dangerous. They are a poor medium for anaerobic botulinum, and cooking takes care of most everything else. It will become unappealing before it ever becomes dangerous. (Ground meats are another matter, coming from their highly questional processing environments.)
"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen