You should document the condition of the property with photographs before you move in.

This will be your evidence to if later you are charged for something that you did not do — or was already that way when you moved in. As @DaleM points out in his below comment, the technical term for this is a ***Dilapidation Report***.

When you fight for your security deposit back if there is a later dispute, it will be a battle of evidence. If you say something was that way when you moved in, then you will need to prove it. Photographs with a timestamp will be useful if not necessary to prove your case.

You can prove the time stamp by posting the photos to a third party web host (like Flicker, Instagram, Tumblr, etc.) that has a reliable timestamp at the time of posting.