Alter Ego Trusts (AET) and Joint Partner Trusts (JPT) are a more complex method of estate planning, but can be well-suited to certain situations. You must be over the age of 65 years to consider these methods of planning.
AET and JPT both are often used as a method of probate avoidance. However, these trusts also are more private than a traditional Will, because your Will is publicly available once your executor files for probate. Where there is no probate, your distribution is not made publicly available.
The downside is that AET and JPT are more expensive and complicated to set up and maintain. They save you probate tax, but unless your estate is large enough you can end up spending more to set up the trust, than you would have paid in probate tax on your death.
Another downside is these trusts have certain reporting requirements and you must file a separate tax return for your trust. This requires the ongoing expertise of an accountant, which also makes for an ongoing expense.
Overall, AET and JPT can be a great method of estate planning if they work for you. Speak to your lawyer about whether this method of estate planning makes sense for you and your situation.