Say what you mean and mean what you say, period. Any disclosure, agreement, easement - whatever - should be complete enough to cover issues, but not so long as to obscure the intent of the parties. I find it helpful to keep the language simple and easy to understand. For instance:
The undersigned buyer understands that the fence in the rear of the property located at _____ is in a state of disrepair, needing full replacement. Buyer and seller have agreed that the buyer will accept the fence in this condition and that the seller will have no further liability in the matter.
Here's a good test when writing any kind of agreement or disclosure. After you write it, have someone who is not familiar with the issue or taken part in any conversation related to the issue read your language. Do they understand the problem and the remedy? Do they understand your intentions without further explanation? If so, you've done a very good job of it. If not, you are not alone. It's really difficult to write something from the perspective of someone who doesn't already have the facts. It's just too easy to assume that because you and the other person have discussed the issue, you have both come to the same conclusions.
Writing out the issue and the agreed conclusion in a way that someone not involved will understand does two things for you. It tests that you and the other party have really come to a "meeting of the minds" and it gives a judge or some other arbitrator clear guidelines for understanding the original intention of the disclosure or agreement.
You have to assume the worst case scenario. Assume that you and the other party will have an argument leading to some outside intervention to resolve differences. If the words you put to paper cannot be understood by an outside party, the conclusion they draw to resolve the dispute may not be anywhere near the original agreement.