Comment by jmyeet

There are several legal principles in play here. Note that these are civil trial issues and when you're talking about "robbing", you're likely talking about a criminal issue. These are:

1. Estoppel. If a party relies on your conduct then you can lose the right to sue over it;

2. Laches. This is a defense against prejudicial conduct, typically by waiting too long to take action;

3. Waiver. Your conduct can waive your right to sue. Imagine you live with someone and they don't pay half of the rent so you cover it. At some point your continued conduct means you lose the right to sue; and

4. The statute of limitations. Some claims simply have to be brought within a certain period. How this applies can be really complex. For example, we saw this in Trump's fraud convictions in New York. His time in office, away from the jurisdiction, essentially suspended the statute of limitations.

Some crimes like murder have no statute of limitations. Others have unreasonably short statutes of limitations. For example, probably nobody can be charged in relation to sex trafficking in the Epstein saga because the statute of limitations is often 5 years with such crimes. This is unreasonable (IMHO) because often the victims are children and unable to make a criminal complaint.

It's also worth adding that not all legal systems have such wide-ranging statutes of limitation as the US does. Founding principles of those other legal systems is that the government shouldn't be arbitrarily restricted for prosecuting criminal conduct. The US system ostensibly favors "timely" prosecution.