Nut or Lactose-Free Milk
Now would be the perfect time to switch to something like a nut-based milk. While whole, reduced fat and skim milk can last around a week or so and you can see them going bad. Almond milk for example, can go for about 10 days once opened. As for lactose-free milk, due to the pasterurization process, it can last for weeks without being opened. When opened, it can last a week past its expiration date.