In more than 30 years of patent law practice, I have seen the same errors come up again and again — mistakes made in the weeks and months before a patent application is ever filed that significantly weaken the resulting patent, or in some cases eliminate the ability to get a patent at all. The frustrating thing is that nearly every one of these mistakes is completely avoidable.

Here are the five most common, and what to do instead.

Mistake #1: Publicly Disclosing the Invention Before Filing

This is by far the most damaging and the most common. Inventors talk about their ideas — to friends, at trade shows, in online forums, to potential investors, to manufacturers they hope to work with. Sometimes they post about the invention on social media. Sometimes they sell or offer to sell the product before any patent protection is in place.

Under U.S. patent law, you have a one-year grace period from any public disclosure to file a patent application. Miss that window and you lose your right to a U.S. patent entirely. But that same grace period does not exist in most other countries. If you publicly disclose your invention before filing, you have typically eliminated your ability to obtain patent protection in Europe, Asia, and most other international markets — permanently.

The solution is simple: file before you disclose, or at minimum file a provisional application immediately if a disclosure becomes unavoidable. If you have already publicly disclosed your invention, contact a patent attorney right away to assess where you stand and whether you are still within the U.S. filing window.

Mistake #2: Conducting a Casual "Google Search" and Calling It a Prior Art Search

Before investing in a patent application, it is worth understanding whether your invention is truly novel — whether anyone has already patented or published something that could prevent you from getting meaningful patent protection. Inventors often Google their idea, find nothing obvious, and conclude they are in the clear.

A casual internet search is not a prior art search. The patent literature — millions of patents and published applications from the U.S. and dozens of other countries — is only partially searchable through Google. A meaningful prior art search uses specialized patent databases (including the USPTO's own database and international equivalents) and requires knowing how to search by technical concept, not just by product name.

A professional patentability search — conducted or supervised by a patent attorney or registered patent agent — gives you a realistic picture of the landscape before you spend money on an application. It also informs how to draft the claims: if there is close prior art, the claims need to be carefully crafted to distinguish around it.

The cost of a patentability search is a fraction of the cost of filing an application — and it can save you from spending thousands on a patent application that, once the examiner finds the prior art, produces a much weaker patent than you expected or no patent at all.

Mistake #3: Filing a Provisional Application That Is Too Thin

A provisional patent application does not require formal patent claims, so many inventors (and unfortunately some attorneys) treat it as an opportunity to file something quick and minimal — a few pages describing the basic concept. The provisional gets filed, the "Patent Pending" label goes on the product, and everyone feels protected.

The problem surfaces 12 months later, when the non-provisional application needs to be filed. The non-provisional can only claim priority to the provisional for subject matter that was actually disclosed in the provisional. If the provisional was thin, vague, or incomplete, you cannot add new features or details to the non-provisional and still claim the earlier priority date for them.

A well-prepared provisional should describe the invention as completely as possible — including all the key variations, preferred embodiments, and alternatives you have thought of. It should read almost like a full application, because its job is to be the foundation the non-provisional is built on. A provisional that fails at this job provides a false sense of security.

Mistake #4: Thinking the Patent Covers More Than It Actually Does

This is less a mistake made before filing and more a misunderstanding that develops during the process — but its consequences play out before inventors realize the problem.

A patent does not protect an idea. It protects the specific claims that are allowed by the USPTO examiner. Those claims are almost always narrower than the inventor imagined when they first thought of their invention. During prosecution — the back-and-forth with the examiner — claims frequently get narrowed through amendments made to get the application allowed. An inventor may walk away with an issued patent genuinely believing their invention is fully protected, only to discover later that a competitor has designed around the claims with a minor variation.

The antidote is to work with a patent attorney who explains the claims to you in plain English throughout the process, so you understand exactly what your patent covers and what it does not — and who fights hard during prosecution to maintain the broadest possible coverage.

Mistake #5: Waiting Too Long to Consult a Patent Attorney

Many inventors come to a patent attorney only after they have already made some of the mistakes above — after the public disclosure, after the DIY provisional, after the rushed filing. At that point, the options are fewer and the costs are higher.

The most common reason for waiting is concern about cost. But a single consultation — which we offer free for the first 30 minutes — costs nothing and can prevent mistakes that cost far more to fix later. Understanding the process, the timeline, the costs, and the strategic options before you take your first step puts you in a fundamentally better position than trying to figure it out as you go.

Even if you ultimately decide to file a provisional application on your own to save money, a prior consultation with a patent attorney will make that provisional significantly more valuable — because you will understand what it needs to contain.

What You Should Do Right Now

If you have an invention you believe has commercial value:

  1. Stop disclosing it publicly until you have a filing date — or understand exactly where you are within the one-year grace period if a disclosure has already occurred
  2. Document your invention thoroughly — write down every feature, every variation, every alternative approach you have considered, with dates
  3. Schedule a consultation with a patent attorney before taking any further steps — the first 30 minutes with us are free

A patent, done well, is a valuable business asset that can protect your competitive position for 20 years and provide real leverage in licensing negotiations. Done poorly — through avoidable mistakes — it can be an expensive document that does not actually do what you need it to do. The difference often comes down to the early decisions.