You don't have to be a Rockefeller to need a trust. A trust can be a useful estate-planning tool for lots of people. But given the expenses associated with opening one, it's probably not worth it unless you have a certain amount of assets.
Here's a good rule of thumb:
If you have a net worth of at least $100,000 and have a substantial amount of assets in real estate, or have very specific instructions on how and when you want your estate to be distributed among your heirs after you die, then a trust could be for you. Trusts are also great for minimizing estate taxes or protecting your estate from lawsuits and creditors.
Trusts are flexible, varied and complex. Each type has advantages and disadvantages, which you should discuss thoroughly with your estate-planning attorney before setting one up.
Take note: Assets you want protected by the trust must be retitled in the name of the trust. Anything that is not titled to the trust when you die will have to go through probate.