But lawsuits don't always demand money damages. Claims can be made for injunctive relief (asking the court to stop something from happening) or for declaratory relief (asking the court to determine a legal obligation). These non-money damage claims are not restricted by statutes of limitations.
The distinction is very important where you are attacking the validity of an old judgment entered against you. It may be that you were not properly served, that your identity was hacked, or that the process of taking a judgment against you was somehow improper or unfair. It may be years before you discover the existence of the judgment on your credit report, or perhaps when you move to a new job.