If the apartment is not clean when you arrive, contact the landlord immediately. You will not be reimbursed for cleaning the apartment yourself, and will be expected to leave it in a clean condition when you move out, no matter what condition it was in when you moved in.
Before bringing your belongings into the rental unit, perform a careful walk-through inspection. Make a list of pre-existing damages. Most landlords will provide you with a form called a move-in checklist. Take pictures of any damages you note, such as stains on carpeting, marks on walls, nicks on floorboards, damages to blinds and problems with bathroom or kitchen fixtures.
If the apartment is furnished, include an inspection of the furniture and photograph the condition of the items.
Return a copy of the move-in checklist to your landlord within the first couple of days after you move in and keep a copy for your records.