irrevocable trusts can remain up and running indefinitely after the trustmaker dies, but most revocable trusts disperse their assets and close up shop. This can take as long as 18 months or so if real estate or other assets must be sold, but it can go on much longer. How long it takes to settle a revocable living trust can depend on numerous factors.
"A trust can remain open for up to 21 years after the death of anyone living at the time the trust is created, but most trusts end when the trustor dies and the assets are distributed immediately."