Hubby and I don't drink enough fresh milk to keep it on hand. I buy a gallon of milk (usually 1%) to make yogurt for the month. Even though I do buy and use almond milk and Coconut Dream (reduced fat coconut milk), occasionally, I don't always keep it on hand either, but I always have instant nonfat milk powder (instant dissolves much better in the water, and tastes better).
For a lot of recipes, any liquid, even water can be used in place of some or all of the milk (sugar free instant pudding even turns out ok with half water and half milk. My grandma used all water). I don't know any sure fire method of learning what will work and what won't except for trial and error.