Suitability of a trust over a will, is a legal analysis that a program or book won't be able to make
A trust can be a "will replacement," but only if set up and handled properly. Doing it right is a certain amount of trouble, not just drafting, but also funding. It's more complicated to draft than a will, more complicated to properly administer during one's own lifetime; and depending on the type of assets in or outside the trust, it may or may not be any less complicated than a will directing an estate in probate court. In fact, unless all assets are named as trust property, one may end up in court administering non-trust property anyways. Oh and where does one go to get a legal remedy if there is a problem? Good old probate court. So to really be an effective "will replacement" that "avoids probate," there are a lot of tasks to be done. So a will may be a simpler way handle things, and a form book won't bother to explain that to you, but a lawyer can do so.
Avoiding the common mistakes that laypeople make with trusts that defeat the goal of "avoiding probate."
In my experience people who use form trusts or trusts prepared by non-lawyer document prep services oftentimes tend to make big mistakes that a lawyer is expected to avoid. Specifically, the biggest non-lawyer trust job mistake is a failure to fund the trust with the assets of the settlor. Then, when the settlor dies, the trust is irrelevant, because it only controls property put into the trust during the lifetime of the settlor. If a settlor never funds the trust with assets, it doesn't matter. A lawyer will almost always recommend a pour over will to fix this. Indeed many non-lawyer trust jobs don't even bother with a pour-over wills, which helps fix the problem by directing assets handled in an estate adminstration to be paid over into the trust at the end. Without a pour-over will, there is no such way of funding a trust post mortem. A lawyer will remind a client about this and explain it and oftentimes assist and follow up. This is very much worth the expense.
Trustee selection issues
Who makes a good successor trustee? Of course a settlor usually wants to be his or her own initial trustee but who makes a good successor? A spouse perhaps but what about for a single person? Who else can do the job well? A lawyer can help someone judge who among trusted friends and family would be best for this job, because the lawyer in estates practice knows the tasks and temperament of a trustee whereas a lay person or doc prep service does not. This is a question of judgment and not just filling in the blanks. Moreover a lawyer can help pick an institution like a bank if no individuals are available, and lawyers know which banks do better than others. The job of trustee is all important choice in this process since the trustee is the one whom both the settlor and the beneficiaries are going to have to trust. They will control the property named in the trust and have more power to abuse than an executor, in general, so don't go cheap on making the right choice.
Problems of tax and title and asset funding choices
Some property is not suitable to be added to a trust. Some property or contractual rights do not lend themselves well to trust adminstration or trust adminstration may cause unforeseen tax problems. Generally it is undesirable, for example, to make an IRA or other qualified retirement plan, payable to a trust. A lawyer can help a person sort out the specific details of all different kinds of property and assets that he or she may have and determine intelligently how to fund the trust and how to handle assets that are not going to be adminstered by it in the end. That kind of detail work is usually a matter of experience and is oftentimes far more complicated such that a checklist type guide won't do.
There is a perception that lawyers charge a lot for trusts. Maybe compared to a document assembly program; and maybe if you discount the hassle of using the software and making the right choices all on one's own. But comparing document prep service jobs for trusts, they are often are priced per item, which will, when all the a la carte items are added together, will not offer significant savings over what a small or solo law firm practicioner will charge. A good estate planning service from a lawyer with wills, trusts, powers of attorney, and designations of health care representative forms will often be more or less the same price once all is done. And likewise, with a lawyer you do not need to discount the mistakes that one self may make or some document assembly worker may do, because only lawyers may be sued for "legal malpractice" and so only lawyers will be really motivated not to mess things up in the first place. Take that into consideration, too, when reckoning value.