Thinking about compost made me realise we don't see many worms at the farm because we don't turn the soil over. I'm sure there must be plenty of them - with all that organic matter around they must love it! Earth worms are essential for good, fertile soil. They help to aerate the soil by tunneling; bring deeper and often nutrient rich soil up into the topsoil; and while they are doing this they secrete a slime that contains nitrogen - vital for healthy plants. They are also an important part of the ecosystem's foodchain - blackbirds love them, so do moles, badgers, foxes, toads.....They can live up to 8 years ( although I don't know how you find out?) but with all those predators their life span is usually quite short. Pollution and pesticides are, of course,also threatening to earth worms - toxins get into the soil and even if they don't kill the worm they can be passed on to their predators, while chemical fertilisers can make the soil too acidic for earth worms to survive. So let's be kind to worms and make sure that there is plenty of soil for them to live in and vegetable matter to eat!