There is no hard or fast rule about how regularly you should update a WIll because it all comes down to personal circumstances. A figure you might see floating around recommends updating your Will every 3-5 years. This is a good basis, but there are also a series of triggers you should be aware of which should prompt you to update your Will.
Your relationship status changes through marriage, divorce or a de facto relationship;
Your spouse dies;
Your Executor or Beneficiaries die or become incapacitated;
You have a new child or grandchild;
You buy or sell property or other significant assets;
You come into an inheritance;
You retire.