You definately need a will if you want to have your assets distributed in a manner that differs from the scheme set out in the Act or if you have dependant children.
You may also benefit from a structuring which lessens tax consequences that might otherwise occur on death. These considerations also apply if you have the potential of gaining significant assets through business, by inheritance, or otherwise.
Another factor is whether or not a person has personal bequests. That is, personal items like family heirlooms, coin collections, jewelry, or such things that you want to give to particular people.
If you possess a valid will, and become married afterward, the will is void. Ironically enough, if you become divorced, your will stays in effect, and your former spouse will receive all of the bequests to which he was entitled under that will. Therefore, if you are either getting married or getting divorced, you should be thinking about having an updated will done.