Patent Litigation Questions for Inventors and Business Owners

How long does a patent case take?

In the busiest Texas patent courts, cases that reach trial have typically done so in about two years from filing. One analysis put the median time to a jury trial in the Western District of Texas at 24.2 months, and the Eastern District's median was shorter. Most cases end sooner, by settlement or dismissal. An appeal to the Federal Circuit adds more time.

What does a patent case cost?

It depends on what is at stake. The American Intellectual Property Law Association's 2025 economic survey, as reported, puts the median cost of a case at about $1 million when $1 million to $10 million is at risk, and about $3 million when $10 million to $25 million is at risk. A challenge at the Patent Trial and Appeal Board costs less, but the Patent Office fees alone for an inter partes review of up to 20 claims are $23,750 to file and $28,125 more if review is granted (37 C.F.R. § 42.15).

Can I be sued for selling or using a product someone else made?

Yes. The patent statute reaches anyone who makes, uses, offers to sell, sells, or imports a patented invention without authority (35 U.S.C. § 271(a)). Customers and resellers are often sued. A merchant seller of goods generally warrants that they will be delivered free of any rightful infringement claim, unless the parties agreed otherwise (Tex. Bus. & Com. Code § 2.312(c)). When a manufacturer and its customers are sued over the same product, courts may let the manufacturer's case go first (In re Nintendo Co., 756 F.3d 1363 (Fed. Cir. 2014)).

The patent has expired. Can the owner still sue?

Yes, for infringement that happened while the patent was in force. Damages cannot reach back more than six years before the suit was filed (35 U.S.C. § 286). A court will not order anyone to stop using an expired patent.

Do I have to respond to a demand letter?

No law requires a response, but ignoring a letter has risks. Once a business knows of a patent, that knowledge can support a later claim of willful or induced infringement. Texas law prohibits sending bad-faith patent infringement letters to end users in Texas, such as a letter that falsely claims a lawsuit has been filed or asserts an expired patent (Tex. Bus. & Com. Code § 17.952). Only the Attorney General can enforce that law (§§ 17.953, 17.955). See Responding to a Patent Infringement Claim.

Does the patent owner have to warn me before suing?

No. But if the owner sells a patented product without marking it with the patent number, damages generally run only from the date the infringer received actual notice, and filing suit counts as notice (35 U.S.C. § 287(a)). The marking rule generally does not apply to patents that claim only methods.

What is an inter partes review, and should I file one?

An inter partes review asks the Patent Trial and Appeal Board to cancel patent claims as anticipated or obvious in light of earlier patents and publications. It must be filed within one year after service of an infringement complaint (35 U.S.C. § 315(b)). A petitioner who loses cannot raise in court the grounds it raised or reasonably could have raised in the review (§ 315(e)(2)). Since 2025, the Patent Office Director decides whether to grant review, and grants have become much harder to obtain. Whether to file depends on the prior art, the court schedule, and the cost.

Can I be forced to stop selling?

Possibly. After a finding of infringement, a court may enter a permanent injunction if the four factors of eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006), favor it. Orders before trial are uncommon. For imported products, the U.S. International Trade Commission can issue an exclusion order barring entry.

Who decides my case, the judge or a jury?

Both. A jury usually decides infringement, many questions bearing on validity, and damages. The judge decides what the claims mean, and decides fees, injunctions, and whether the patent is unenforceable for inequitable conduct.

What is willful infringement?

Infringement that is deliberate or egregious. A court may then increase damages up to three times (35 U.S.C. § 284; Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016)). Failing to obtain a lawyer's opinion cannot be used to prove willfulness (§ 298).

Can I recover my attorney's fees if I win?

Only in an exceptional case, one that stands out for the weakness of a party's position or the unreasonable way the case was litigated (35 U.S.C. § 285; Octane Fitness, LLC v. ICON Health & Fitness, Inc., 572 U.S. 545 (2014)). Otherwise each side pays its own lawyers.

Can I ask a court to rule first that I do not infringe?

Yes, if there is an actual controversy, such as a specific threat of suit. A declaratory judgment action lets the accused party choose the court (MedImmune, Inc. v. Genentech, Inc., 549 U.S. 118 (2007)), within the venue rules.

Will my insurance cover a patent suit?

Often not. Many commercial general liability policies exclude patent infringement. Some businesses buy separate intellectual property coverage. Read the policy and give notice promptly, because late notice can forfeit coverage.

What is a nonpracticing entity?

A patent owner that licenses or sues on patents rather than making products. The same patent law applies. The difference is practical: such an owner usually seeks money rather than an order to stop sales, and it has no products against which to bring counterclaims.

Sources.

• 35 U.S.C. §§ 271(a), 284-287, 298, 315; 37 C.F.R. § 42.15; Tex. Bus. & Com. Code §§ 2.312(c), 17.952-17.955
• eBay; Halo; Octane Fitness; MedImmune; In re Nintendo
• Docket Navigator, "How top US patent courts compare on median time-to-trial statistics" (June 27, 2022)
• AIPLA 2025 Report of the Economic Survey, as reported by IPWatchdog (Oct. 1, 2026)

This guide is general information, not legal advice. Law checked through October 20, 2026. See the Disclaimer.