You should document the condition of the property with photographs before you move in.
This will be your evidence 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 this is called 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 claim something was that way when you moved in, you must 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 image host (like Flicker, Instagram, Tumblr, etc.) that has a reliable timestamp at the time of posting.