This can be a general "when will this go bad/will this go bad if..." thread, I guess!

I'm interesting in making Alfredo sauce. It's my favorite, and it's the thing that makes Chicken Carbonaras so exceptional. I want to make a big batch of it and put it on all of my sandwiches.

If I make it in a semi-large quantity, does anyone how long I have until it will go off? It's mostly made of butter and cheese, and while cheese stays okay for a while, I honestly don't know how long you can have it stored in the refrigerator, and if it'll be bad if reheated. I'm not interested in storing it for a month, just a week or so. Any chefs or expert cooks? Saucemasters (doesn't that sound like a really useless job in Dwarf Fortress?)

Alternative topic; what was the most disgusting discovery you found of something that was left to go rotten in the fridge/in a mystery place? :x