In California, a typical estate planning tool is the revocable trust. A husband and wife usually create one jointly, with the two of them serving as co-trustees until one dies. Then the other becomes the sole trustee. When the surviving spouse dies, the trust will usually name a successor trustee to take over the responsibilities of trustee.
A key feature of a revocable trust is to recognize that what was once a revocable trust becomes an irrevocable one when both of its creators/settlors/grantors die ( a portion of it could become irrevocable on the first death, depending on the language of the trust).
As the successor trustee, one of your responsibilities is to notify all named beneficiaries of the trust and heirs of the decedent that the trust has become irrevocable. This is as set forth in California Probate Code §16061.7, which prescribes the notice that is to be given by the successor trustee.
The notice is typically served by mail and the statute provides that it is to be sent within 60 days following the death of the surviving settlor (i.e. within 60 days of the event that made the trust irrevocable).
Generally, in at least 10 point boldface type, the notice must, among other things, separately state that:
"You may not bring an action to contest the trust more than 120 days from the date this notification by the trustee is served upon you or 60 days from the date on which a copy of the terms of the trust is mailed or personally delivered to you during that 120-day period, whichever is later."
This language starts a 120 day statute of limitations; if no one contests the trust within that 120 day period, no trust contest is generally possible by anyone given proper notice. This is a benefit, in that it provides some certainty to the trustee that the trust can be administered and the property distributed without fear of litigation, once the 120 day period has run out.
It is also a detriment to one unhappy with the terms of the trust; they only have 120 days to decide whether to file a contest, no more. If you are the contestant, consult competent counsel in a timely manner before deciding whether to litigate.