There’s nothing to be afraid of. The temperatures the oil is heated to will kill any germs. I throw away the oil when it smells or tastes unpleasant. It helps prolong its life to filter it through cheese cloth or maybe a coffee filter to remove any bits of breading or other food debris after each use. It’s also probable that if you cook seafood or other strong-flavored foods, you won’t get as long a life out of it. Oh, and I’ve read that intermittently cooking potatoes (French fries or other) in it actually helps "renew" it by absorbing "off" flavors.