There are two debt clocks, and each is important.
First is the clock for forcing collections on a debt, which is often called the "statute of limitations on collections." It varies from state to state. Typically, it's three to six years. In some states, it can be up to 15 years.
This is the clock you have to consider if you're worried about reviving the possibility of forced collections on an old debt.
The second clock is the length of time a debt can stay on your credit report and, as a result, affect your credit score. That clock runs for seven years.
The credit-report clock on a delinquent debt starts six months after you stop paying, says Chi Chi Wu, staff attorney with the National Consumer Law Center. No matter when the bad debt popped up on your credit report, it has to come off seven years after the clock started ticking.
Nothing you or anyone says or does can restart this clock, says Wu.