When reheating, it depends on the consistency of the sauce. If it's a heavy version, it'll go all sorts of downtown when you reheat it, and trying to put it back together may be messier than you might like (not that this is an excuse not to eat it, it'll still taste like alfredo sauce, just in its separate parts). Doesn't matter how long you store it, in my experience;just happens.
I make alfredo sauce for myself all the time, but I don't think past three days anymore. Sure, something can be saved if you freeze it, but the effort required to reheat and maintain its consumable integrity is just so not worth it.
Now, if you're talking about tomato based sauces, that's definitely something different.