"Chicken stock is super easy to make with your left-over bones, plus you can throw in all your other "weird" bits like tough cartilage and fat."
Exactly. If you make a true bone broth, the bones will be soft and useless at the end, and the broth will be mineral-rich and gelatinous (upon refrigeration). To do this, you need to let the bones "rest" in a slightly acidic medium for a while before bringing to a rapid boil (I use a 1/2 cup of apple cider vinegar in the full stock pot of water ~16L) and then simmering for 24 hours at very low heat - on my stove, it's level 1. Just hot enough that bubbles break the still surface, but not actually making the surface ripple. The resulting broth is deep amber, clear, and forms a gel-like consistency in the fridge. This is excellent sipped slowly for anyone who is sick, or to make nourishing soups and sauces. I freeze veg that are close to spoiling to throw in too.