The turkey I bought (I think it was Jennie-o brand) had a pouch of gravy concentrate tucked inside. I'm always suspicious of those sorts of things and make my own gravy if I want gravy. But this year I was trying to keep everything simple. The directions said to add 2 cups of water or broth. I had plenty of watery drippings from the roaster (that later went into the stock after I boiled the carcass) but figured that would have too much salt, and the gravy mix was probably too salty already. So I boiled the giblets and neck in about 3 cups of water to make broth and I used that. The gravy was still too salty, but not bad.
Leftovers time, I decided to thin the gravy out a little with some half-n-half and see what I got. Added less than a cup but not much less, and brought it to a simmer and stirred it up good. Also gave it a couple of grinds of black pepper. Damn, that was good! There's still a little left, but not much; I've been eating it with potatoes and leftover turkey. I need to try some on a baked sweet potato before it's all gone...
I'll know next year to start out like that. And now you know too.