There are different types of testamentary trusts, including discretionary trusts and special disability trusts.
Testamentary trust may assist to distribute your estate to your beneficiaries in a more tax effective manner and may reduce the likelihood of a successful challenge to your Will.
It is a common practice for the trustees of a discretionary trust to distribute any derived gains to those beneficiaries who have the lowest marginal tax rate in the distribution year. This is one of the main advantages of using a testamentary trust.
A testamentary trust may also provide asset protection for beneficiaries of your estate who may face certain legal claims on their assets, divorce or bankruptcy.