What has happened is that some collection companies purchase this debt from lenders for pennies on the dollar and attempt to collect on expired debt through harassing phone calls or even lawsuit. The persons they are trying to collect from often are unaware that the debt is past the statute of limitations and therefore collection is unenforceable through the court system.

The time limit for the statute of limitations varies from state to state and claim to claim. It is also possible to bring multiple actions for a single debt or conduct. This means that even if one statute of limitations has expired on one cause of action, it may not have expired on a different cause of action for the same debt.

In general terms, the statute of limitations on written contracts like mortgages, credit cards, and car loans is six years. Fraud claims like 'embezzlement' or theft is also six years. Medical malpractice is two years, whereas most other personal injury claims based on allegations of negligence, as well as products liability, the statute of limitations is three years. If a judgment is obtained, the statute of limitations on the judgment is ten years, and can be renewed by application after ten years.

Finally, a statute of limitations may become "tolled" during a bankruptcy. If the bankruptcy is dismissed without a discharge, the clock on the statute starts ticking again for the remaining time period of the claim.