Getting a trust to avoid having your estate go through probate is only effective if you fund the trust. That means your assets need to be transferred into the trust. Any assets held in the trust when you pass away will then be used and distributed according to the terms of the trust instead of having to go through probate.
At the same time, you will also likely get a pour over will.
These are simple wills that dictate that any assets you had at the time of death that are not in the trust should be placed into it via probate.
Do not let that fool you into thinking you do not need to transfer assets to the trust now and just rely on your will as the Green Bay Press-Gazette points out in "Estate Planner: Importance of funding your trust."
While the exact rules vary from state to state, it does not take a lot of assets to require an estate to go through probate.
If all of your assets remain outside of your trust, then your executor has to probate your pour over will. By relying on the will you would have essentially defeated the purpose of getting the living trust in the first place.
If you do not know how to transfer assets into your trust or need assistance doing so, then talk to your estate planning attorney to get more information about what you need to do.
Reference: Green Bay Press Gazette (Oct. 31, 2016) "Estate Planner: Importance of funding your trust."