Motor oil
You should be changing the oil in your car regularly, to ensure the highest level of engine performance. Your oil itself needs to be kept an eye on too. It should last around 5 years, as long as it is kept in a cool and dry place.
To check its usefulness you should look at its consistency, which shouldn’t be thick or sticky. However, this depends on the oil’s original viscosity rating. There shouldn’t be any large lumps in it. If any of this is the case then you shouldn’t be using it in your car, lawn mower, or other vehicle.