To make or update a Will you must have testamentary capacity.

As we age, our memory may not be as sharp as it once was. You or a member of your family may become concerned about your testamentary capacity. Or you may be suffering from a capacity-impairing illness, such as dementia. If so, this does not mean that you cannot provide instructions for your Will as capacity may fluctuate.

Testamentary capacity is a legal test not a medical test. A specialist, experienced Wills and Estates lawyer who you trust can determine whether you have testamentary capacity.

What is the test for testamentary capacity?

The key test to establish testamentary capacity is according to the English case of ‘Banks v Goodfellow‘ from 1870. This case sets out four requirements that you must meet to establish testamentary capacity.

  1. Understand the nature and effect of a Will. It is very important that you understand and know that you are creating a Will and the purpose of a Will. Consideration should be given to who you would like to appoint as the Executor and Trustee and how your assets will be divided upon your death.
  2. You should be aware of the nature and extent of your assets and how these assets are held, eg. individually, jointly or in a Company or Trust. The current value of assets held should also be known.
  3. You must understand who should be considered (potential beneficiaries) and also understand the effect of any claim which may be made against the estate.
  4. You should have no disorder of mind which would affect your decision-making capabilities to make rational decisions on how to distribute the estate.

What happens if the lawyer questions your capacity?

It is likely that the lawyer will require a report from your medical practitioner. A report from a medical practitioner is a safeguard against a challenge that a Will is invalid on the grounds of lack of capacity.

The lawyer will request the following information:

  • How long have you been their patient?
  • When did the medical practitioner last see you?
  • Brief account of your overall health.
  • Conclusion of whether you have capacity to make a Will and understand the concept of the ‘Banks v Goodfellow‘ test which the lawyer would outline to the medical practitioner.

Based on the above the lawyer may or may not be able to prepare a Will.


If a medical practitioner’s report is required by the lawyer, it should not be taken as an insult to intelligence or ability, rather as a safeguard to ensure your Will is not challenged after you pass away.

Turner Freeman Lawyers want to ensure as best we can that you have capacity, and your Will is therefore legally binding.

If you feel you need some advice regarding your Will please contact our specialist in this area, Tammy Sava, Senior Associate of our Wills and Estates team, located at our Adelaide and Aberfoyle Park (by appointment) offices. Tammy will assess your requirements and provide personalised advice. Contact us today on (08) 8213 1000 to arrange a time to meet with Tammy.

*We recommend you seek sound legal advice whenever something personally or financially changes in your life as you may be required to update your Will.