Prenups rarely fail because Florida courts dislike them — they fail because of specific, recurring drafting and process mistakes that a litigator can spot from across the room. We know, because reviewing and attacking other lawyers' agreements is part of this practice. Here are the twelve defects we see most, why each one matters under Florida law, and how a properly built agreement avoids them.
1. The template from the wrong state
Internet forms and out-of-state templates are written to someone else's statute. They waive things Florida does not allow to be waived (temporary support during a dissolution — unwaivable under the Belcher line), omit things Florida requires (two subscribing witnesses for the section 732.702 estate waivers), and cite community-property concepts Florida does not use. A Florida agreement must be drafted to section 61.079, the probate code, and the 2023 alimony framework — not to a generic "State of ______" blank.
2. Vague or stale disclosure schedules
"Various investments, approx. $500k" is not fair and reasonable disclosure — it is the first exhibit in the challenge. Schedules must itemize assets, liabilities, income, and material expectancies, dated close to signing. If the wedding slips a year, the schedules get refreshed. Our disclosure page covers the full build; the mistake to avoid is treating the schedules as an afterthought stapled on at the end.
3. Waiving what cannot be waived
Three clauses instantly mark an amateur document: capping or waiving child support (barred by section 61.079(4)(b)); pre-deciding custody or time-sharing (courts decide best interests at the time of the case); and waiving temporary support and fees while a divorce is pending. Beyond being void, these clauses do collateral damage — they let opposing counsel argue the whole document was drafted with an overreaching hand.
4. The unrepresented spouse with no record
Florida permits an unrepresented party to sign — and challengers feast on it. The mistake is not the absence of counsel; it is the absence of a record: no written urging to get a lawyer, no time allowed for it, no signed acknowledgment of the declined opportunity. If your fiancé(e) will not retain counsel, the agreement must prove the door was held open. Better: make independent review happen. It is the single strongest enforcement fact there is — see execution & independent counsel.
5. Signing in the shadow of the altar
No statute forbids a wedding-week signing; every voluntariness challenge is built on one. First presentation late, terms changed late, "sign or the wedding is off" — that fact pattern turns a contract case into a duress case. The fix is calendar discipline (our timing page lays out the schedule) and, when time has truly run out, the professional judgment to choose a postnup over a pressured prenup.
6. Ignoring appreciation and commingling
The most expensive silent defect. Florida's default rules pull the active appreciation of separate assets — and separate funds commingled past tracing — into the marital estate. An agreement that says "the business is his" but says nothing about its growth, its income, or the joint account the distributions land in has protected almost nothing. Strong drafting defines separate property to include appreciation and income, sets commingling rules, and pairs the paper with clean banking habits.
7. The ERISA blind spot
"Each party waives all rights in the other's retirement accounts" reads fine and does nothing for employer plans. Federal law recognizes only a spousal waiver of qualified-plan survivor benefits, signed on plan forms after the marriage. The agreement must obligate the post-wedding consents and someone must actually obtain them. We find this hole in a large share of the agreements we review — including some drafted by real law firms.
8. Estate waivers without the two-witness formality
Elective share, homestead, exempt property — waivable before marriage under section 732.702, but that section requires the waiver be signed in the presence of two subscribing witnesses. A prenup signed by the parties alone may hold for divorce purposes yet leave its death-rights waivers open to attack in probate, where the stakes are often larger. Every serious signing should be witnessed and notarized as a matter of course.
9. Alimony math that ignores 2023
Agreements drafted from pre-2023 assumptions negotiate against a statute that no longer exists: permanent alimony is gone, durational alimony is capped by marriage length (50%, 60%, 75% for short, moderate, long marriages), and the definitions changed. A waiver or formula should be priced against the current default — otherwise one side is trading away more than they think, which is exactly the kind of imbalance that fuels an unconscionability argument when paired with disclosure gaps.
10. No severability, no choice of law, no amendment clause
Three boilerplate clauses that are anything but. Severability quarantines a bad term so it cannot infect the agreement. Choice of law (expressly authorized by section 61.079) anchors interpretation to Florida when you move — and clients move. An amendment clause requiring signed, witnessed writings prevents the "we orally agreed to tear it up" testimony that otherwise haunts enforcement twenty years later.
11. Death provisions that fight the estate plan
A prenup that waives the elective share while the will, trust, and beneficiary designations still say something else does not fail — it litigates. The agreement, the estate plan, and the beneficiary forms must be reconciled after the wedding, and re-checked after major events. The prenup should be drafted by someone thinking about both courtrooms: family and probate.
12. Losing the originals
The quietest catastrophe. Twenty years on, the enforcing spouse produces an unsigned Word file and a memory; the challenging spouse produces doubt. Duplicate originals, separately vaulted, with counsel's execution file preserved — it is unglamorous, and it decides cases. Where the documents should live, and how to keep an agreement provable for decades, is the subject of our enforcement page.
What this list means if you already have a prenup
If you recognized your own agreement in more than one item above, the answer is usually not panic — it is a review and ratification. We examine the agreement and its execution history on a flat fee, tell you plainly which defects matter on your facts, and where warranted, cure them with an amendment executed with full formalities and refreshed disclosure. Done in calm times, ratification converts a vulnerable document into a durable one. If you are on the other side — worried the agreement you signed is defective — the same review tells you honestly what a challenge would look like. Either way, better to know now than in the second week of a divorce.
Common questions
We review anything — but understand what review of a template can and cannot fix. Wording we can tighten; a broken process we cannot retrofit. If the disclosure was thin, the timeline rushed, or the execution unwitnessed, the fix is effectively re-doing the engagement properly. For most couples the flat fee for doing it right the first time is close enough to the template-plus-repair path that the template saves nothing but confidence.
Disclosure — by a wide margin. It is the element woven into the statute's own enforcement test, it is where concealment and carelessness look identical years later, and it is the defect least fixable after the fact. Timing and the unrepresented-spouse record are the next two. Notice that all three are process failures, not wording failures: the paragraphs can be perfect and the agreement still dies on how it was made.
No. Florida courts sever unenforceable terms when a severability clause and the equities allow, and many defects merely weaken rather than kill. The dangerous defects are the ones that go to formation — involuntariness, fraud, duress, overreaching, or unconscionability plus failed disclosure — because those support setting aside the entire agreement. That is why process defects outrank wording defects on this list.
Once married, any new or amended agreement is postnuptial — governed by the Casto framework, with the stricter disclosure expectations that apply between spouses. That is not a problem; a ratification amendment executed with full formalities and current schedules is precisely how vulnerable prenups get cured. It simply means the fix must be built to the postnup standard, which we cover on the postnuptial agreements page.
Have an agreement — or a draft — you're not sure about?
Flat-fee review with straight answers. Call (407) 749-1034 or request a confidential consultation.
General information about Florida law — not legal advice, and no attorney-client relationship is created by reading it. Authorities referenced include §§ 61.079, 61.08, 732.702, Fla. Stat., Belcher v. Belcher, 271 So. 2d 7 (Fla. 1972), and Casto v. Casto, 508 So. 2d 330 (Fla. 1987) (verified July 2026). Every situation turns on its own facts.