What Restrictions Do:

Partners use the assets for their own well being, but cannot change the beneficiaries of the trust or give all the money away during life.

Pros:

Cons:

It is hard on the surviving partner, there is a lot of paperwork and risk.
Partner will have a legal obligation to track and discuss how they are using money for the rest of their lives - how much they have, where it is, and how they have been spending it.
Partner can get sued for not keeping track of expenses and following the rules.
Partner may not be able to qualify for home loans or mortgages, including equity lines of credit.
Property in this trust may have sub-optimal tax treatment
It is unrealistic to expect this will work if they live a long time.

Bottom Line:

We only recommend these provisions if both parties are over 60, the limitation only applies to a specific asset, if you have a blended family, or if partner will never need it (have enough $).