As a parent of two sons diagnosed on the autism spectrum, I have first-hand experience with the financial strain that comes with special needs planning. The early years are especially disorienting: navigating diagnoses, therapies, and specialists while watching costs accumulate faster than you expected.
A 2014 JAMA Pediatrics study estimated the lifetime cost of supporting a person with autism and intellectual disability at $2.4 million ($1.4 million without intellectual disability). Adjusted for inflation, those figures are higher today. The numbers are daunting, but the costliest mistakes in special needs planning are not about spending too much. They are about structuring things wrong.
Here are the four mistakes I see most often, and how to avoid them.
Mistake 1: Not Documenting Your Child's Needs
Parents carry an enormous amount of knowledge about their child in their heads: medical history, daily routines, behavioral triggers, preferences, what works and what does not. If something happens to you, that knowledge disappears unless you write it down.
A Letter of Intent is a detailed guide for anyone who may one day provide care for your child. It covers medical needs, daily routines, living preferences, social connections, and your vision for their quality of life. It is not a legal document, but it is the most important reference your successor caregivers will have.
The Letter of Intent also serves as the foundation for your financial plan. You cannot estimate the cost of care if you have not defined what care looks like. It informs how much to fund a trust, what government benefits to preserve, and what level of support your child will need across their lifetime.
Start the letter now, even if it is incomplete. Update it annually. For a framework that connects the Letter of Intent to the rest of your plan, see our four pillars of special needs financial planning.
Mistake 2: Leaving Money Directly to Your Child
This is the most financially dangerous mistake on this list. When adults with disabilities rely on means-tested government programs like Supplemental Security Income (SSI) and Medicaid, those programs impose strict asset limits. The SSI resource limit is $2,000 for an individual. Countable assets above that threshold disqualify your child from benefits.
Well-intentioned parents, grandparents, and relatives who leave money directly to a person with a disability can inadvertently push them over the asset limit and eliminate access to the support services they depend on.
The solution is a Special Needs Trust (also called a Supplemental Needs Trust). Assets held in a properly structured third-party special needs trust are not counted toward SSI resource limits. The trust can pay for supplemental needs -- things government benefits do not cover, like recreation, transportation, technology, and personal care beyond the basics -- without jeopardizing eligibility.
Equally important: communicate the trust's existence to everyone who might leave your child money. Extended family, godparents, friends. If a well-meaning aunt names your child directly in her will, those funds bypass the trust and count as your child's assets. I have seen this happen in my practice more than once.
For a comparison of trust types and when each applies, see ABLE Account vs. Special Needs Trust. For guidance on selecting the right person to manage the trust, see how to choose a trustee for a special needs trust.
Mistake 3: Waiting Too Long to Start
Nobody knows what tomorrow brings. The earlier you establish a financial plan for your child, the more time you have for compounding, insurance underwriting, and trust funding to work in your favor.
Many parents worry that it will take a lifetime of earnings to fund a special needs trust adequately. That is not necessarily true with proper planning. Two tools make early action especially powerful:
Life insurance. A term or permanent life insurance policy naming your child's special needs trust as beneficiary ensures funding even if something happens to you before the trust is fully funded through savings. The younger and healthier you are when you apply, the lower the premiums. See our guide on life insurance and special needs trust funding.
ABLE accounts. An ABLE account allows your child to accumulate savings for qualified disability expenses (housing, education, transportation, health care, assistive technology) without affecting SSI eligibility, up to $100,000 in the account. For 2026, the annual contribution limit is $20,000. ABLE-eligible individuals who work and do not participate in an employer retirement plan can contribute an additional $15,650 above the standard limit. Starting in 2026, ABLE eligibility expanded to include individuals whose disability onset occurred before age 46 (previously age 26). See our guide on the ABLE age expansion for details.
The combination of a special needs trust, life insurance, and an ABLE account creates a layered funding strategy that does not depend on any single source.
Mistake 4: Not Working With the Right Professionals
Special needs financial planning sits at the intersection of estate law, tax law, government benefits law, and investment management. The rules are technical and the consequences of mistakes are severe: a single error in trust language or beneficiary designation can disqualify your child from benefits they depend on.
This is not an area where general-purpose financial planning is sufficient. You need professionals who understand how SSI, Medicaid, ABLE accounts, special needs trusts, and guardianship alternatives interact. Your team should include a fiduciary financial advisor with special needs planning experience, an estate attorney who drafts special needs trusts regularly, and (depending on your situation) a benefits counselor or elder law attorney.
Coordination matters as much as individual expertise. Your financial plan, your estate documents, and your government benefits strategy need to work together. A trust drafted without understanding the financial plan may be underfunded. A financial plan built without understanding benefits eligibility may inadvertently disqualify your child.
For a broader view of what to expect from a planning engagement, see what to expect from your special needs planner. For guardianship and legal considerations when your child approaches adulthood, see our guides on guardianship alternatives and when your child turns 18.
What These Mistakes Have in Common
All four mistakes share a root cause: delayed action. Parents are managing the daily demands of raising a child with a disability, and long-term financial planning gets pushed to the back burner. That is understandable. But the cost of delay compounds: insurance gets more expensive, trust funding falls behind, and the risk of an unplanned event catching you without a plan increases every year.
The single most productive step you can take is scheduling a planning conversation. Not to commit to a specific product or strategy, but to understand what the plan needs to include and what is most urgent for your family's situation.
For a comprehensive overview of special needs financial planning, see our special needs planning guide.
If you would like to discuss special needs planning for your family, start a conversation with us.
