Generally, I don't have enough bones to make bone broth   I've got a low calorific intake, live alone, eat a lot of fish, and eat away from home a lot, which means I rarely have enough bones.

I make bone broth often and freeze it in 1 cup servings, so I can take out a serving at a time.  I cook just for me.

I save every bone I get.  Here is how I make my bone broth.  First roast the bone for 1 hr at 350 F.  Put bones and any scraping into a crock pot and cover with water.  Add 4 Tablespoons Braggs Vinegar.  Cook on low for 24 Hrs.   Add a couple of bay leaves, hand full of chopped carrots, hand full of onion and a hand full of celery.
Cook on low for another 24 hrs.  Add black pepper and salt to taste.  Strain and freeze.  I freeze the left over bones and stuff for next time.  I usually have a cup every other day and add the broth to the soups and stews
I make.