A well drafted estate plan is intended to last many, many years. It is my hope that my clients ride off into the sunset with their estate plans and do not need any updates. However, life is anything but constant, so sometimes changes are necessary. It is important to revisit your estate plan every few years and when you and your immediate family experience major life events--for example: marriages, divorces, births, deaths, buying/selling a home or winning the lottery--to make sure your plan still matches your goals.
An oral contract is, in most circumstances, just as enforceable as a written contract. Of course, the law always prefers written agreements because it is easier to define each party's rights and obligations by looking at a document. So if you have an oral agreement with another party, it is almost always better to put it in writing. This avoids confusion later. But if you do put an agreement in writing, it's important to know about the "parol evidence rule" and how that might affect what is in the contract, and what is not.