No one-size-fits-all answer exists. Every state has time limits, called statutes of limitations, and the time within which you must file a lawsuit varies according to the type of claim, even within the state.
For example, rules in one state might allow a plaintiff with a personal injury claim (such as a broken leg) one year from the date of injury to file suit, and a plaintiff with a breach of contract claim (such as failure to make good on a promissory note) four years from the date of breach to sue. In another state, plaintiffs could have two years for personal injury cases, and five years for breach of contract claims.
For various statutes of limitations in your state, see Chart: Statutes of Limitations in All 50 States. Consider consulting a lawyer if you might have a claim or someone might have a claim against you; the rules can be complex.
Once you've figured out what statute of limitations applies to your case, your next step is to determine when the clock starts ticking. Usually, the time begins to run on the "date of harm"—that is, on the date when you were injured, your property was harmed, or a contract or agreement was violated.
However, another part of this general rule exists. It protects plaintiffs during the time when their not aware that they've been harmed—which could be for months or even years. In such cases, statutes of limitations will start the clock ticking either on the "date of discovery" of the harm or on the date on which the plaintiff "should have discovered" the harm. In short, for some types of legal actions the statute of limitations clock can start ticking at three different times!
The law is complex. The best way to protect yourself is by consulting with a lawyer about exactly how long you have to pursue a lawsuit—and what kind of lawsuit(s) you can pursue.
Example 1: On January 1, a doctor performs a gallbladder operation on Phoebe but mistakenly removes Phoebe's spleen. The doctor tells Phoebe of the surgical error as soon as she wakes up. Phoebe's time period for suing the doctor begins to run on January 1, since the harm occurred on that date and Phoebe actually knew about it. If a two-year statute of limitations for medical malpractice applies to Phoebe's case, she'd have two years from January 1 to file a lawsuit against the doctor.
Example 2: The facts above apply except the doctor doesn't tell Phoebe about the surgical screwup. Phoebe is in constant pain following the January 1 surgery. A month later, on February 1, Phoebe talks to another doctor who tells her that she should not be in pain and that she should immediately come in to have it checked out. Phoebe delays going to the doctor until July 1 of the same year, at which time she finds out that her spleen had been removed mistakenly on January 1. In this situation, Phoebe's time period for suing the doctor probably begins to run on February 1, because the pain coupled with the second doctor's advice determines when Phoebe reasonably should have discovered the harm.
Example 3: Same case, except that Phoebe suffers no unusual after-effects following the January 1 surgery. Phoebe is unaware that anything went wrong with the surgery until July 1 of the same year, when an X-ray during a routine medical checkup reveals that her spleen was removed. In this situation, since Phoebe did not discover and could not reasonably have discovered the harm until July 1, most states would measure Phoebe's time to sue from July 1.
No, but statutes of limitations generally allow at least one year. Except for when you sue a government agency, you almost always have at least one year from the date of harm to file a lawsuit, no matter what type of claim you have or which state you live in. In short, you should have no statute of limitations worries if you sue within this one-year period.
Example: Henry is injured in an auto accident on February 1. On March 1 of the same year, a lawyer whom Henry hires recommends that he seek compensation for his injuries from the driver of the other car. Henry spends months trying to settle with the other driver's insurance company. Finally, on September 1 of the same year, the insurance company writes to Henry that "We'll pay you $1,000, nothing more." Henry concludes that the offer is grossly inadequate and decides to sue the other driver. If Henry isn't sure of his state's statute of limitations for personal injury cases, he should be sure to file the suit before February 1 of the next year and his complaint will definitely be timely.
For various statutes of limitations in your state, see Chart: Statutes of Limitations in All 50 States.
Once you file a complaint on time, a statute of limitations has nothing to do with how long it takes for a case to conclude. However, most states do have separate "diligent prosecution" statutes, which require you to move your case to trial within a certain time period or face dismissal.
An experienced lawyer should be able to explain the ins and outs of the timing issues involved in your case.
No, judges rarely throw out late claims on their own. Defendants must bring to the court's attention any statute of limitations violation.
To be sure that a judge dismisses an untimely case, you include an "affirmative defense" in your answer, alleging that the plaintiff's complaint is untimely. As an alternative to filing an answer, in some courts you can file a Motion to Dismiss, asking a judge to throw out an untimely complaint.
If you are a defendant who thinks that the plaintiff may have waited too long to sue, you'll need to check the applicable state or federal limitations period to determine whether the lawsuit is timely. (You might want to speak to an experienced lawyer, who should be able to explain this complicated area of law.)
Often you cannot sue a government agency unless you first file an administrative claim with the city, county, or state of which the agency is a part. And you may have as little as 60 days to submit an administrative claim. If (as usually happens) the government denies your claim, the denial letter will tell you how long you have to file a lawsuit in court. For example, you have two years to file a claim against the federal government based on negligence. Check your state's rules quickly after you suffer harm, and consider talking to an attorney for a full explanation of the relevant time periods.
Below you'll find California's statutes of limitations for several common types of lawsuits. These are just broad overviews. Be aware that the law changes and that the rules can be more complex than indicated here. An experienced lawyer should be able to explain the relevant law as it applies to your situation.
Note: In 2020, the California legislature "revived" claims for child sexual assault that had expired under prior law. (Before 2020, the limitations period was the date the victim turned 26 or three years after the victim discovered or should have discovered related adulthood psychological injury or illness.) Victims whose claims had expired as of January 1, 2020 were given three years from that date to bring their claims, unless the limitations period for childhood sexual assault that's described above would give them more time than that. (Cal. Civ. Proc. Code § 340.1 (2020).)