The Earth faces so much change so often because of several different reasons. Like the wonderful answerer down below said, gravity is in factusing its gravity to pull things, changing the surface in doing so. But this isn't the only reason. Another reason is because of all the human activity going on. Human activity is changing the world constantly. An example of this would be cutting down trees in an environment. This takes away air, killing more and more animals and such.
Many other reasons stand for the constant evolving of the planet we know and love.
Real quick, I will tell you why i think it does from a scientific point of veiw, but I dont know for sure.
The reason that the Earth goes through so much change on a regular basis is because of Gravity. What Gravity is doing is pulling objects to the Earth that it can reach (Which you probably knew) and so when it does this, it is pulling at the earths surface as well, causing constant change.
