One of the most important elements of proving a slip-and-fall claim is demonstrating the the owner of the premises knew or was on notice of dangerous condition, some time before the slip-and-call injury. After all, the owner or the operator of the property is generally held liable only if he/she knew or had a reason to know of the dangerous condition, and failed to take action to remedy it.
Thus, if you notice a condition on the property that you might be using or renting, it's in your best interest to notify the owner of that condition in writing. If there is no response to your letter/fax/e-mail and the property owner doesn't fix the condition within a month or so, continue follow up in writing. Make sure that you have a proof that your letters were received. If you send a letter by mail, make sure that you receive confirmation of delivery. If you fax your letters, keep the facsimile transmission confirmation sheets, and if you e-mail, request read-receipt (although usually it is presumed that an e-mail was received).
Later, if you have the bad luck of being injured because of the dangerous condition that wasn't repaired as requested, those letters will be critical evidence in proving negligence and your ability to recover for your injuries and damages.