The easier scenario to think about where statutes of limitation really make sense is in collection of payment through the court system. Suppose you buy something on post-payment terms and then the supplier bumbles around forgetting to bill you for it. At what point should you reasonably be expected to pay the bill? In my state you get 7 years, and I think that's probably pretty generous because it covers the entire tab from when you get the thing to when you start a proceeding in court.

For a robbery that doesn't involve a weapon I think we should generally forgive and forget if it's been long enough. Nobody cared enough to bring action in court for whatever reason, and it would be awful for someone in their 40's to be jailed and brought into court for something that happened in their 20's. At that point if the government fails to prosecute that's on them, and on us for failing to hold them accountable. But 20 years is a long time and people can change over that timespan, so it probably doesn't make sense to hold a grudge for that long.

There are especially egregious crimes that have no statute of limitations like murder and sexual assault, but we might find our society better off for keeping the statute of limitations for injuries that we can recover from.

Evidence degrades, memories fade, witnesses die. Generally the worse the crime, the longer the statute of limitations. Murder in most places has no limit.

Also, if someone hasn't committed a crime in, say, 20 years, there's questionable need to lock them up for three years to deter the behavior. Goal is to optimize the overall system even if some people slip through the cracks.

Not a lawyer but generally it is as you say: "because the trials suck after a while cuz no one remembers anything". It's not fair to have a trial when the evidence is unreliable because of the flow of time.

Encouraging timely action is another factor. Generally people with real harms will file sooner than later, otherwise why wait?

It's also to grant peace of mind -- so people can stop worrying about potential litigation after some amount of time.

Are you asking about criminal or civil law? This was a civil case. The general reason for imposing filing time limits is that it's better for businesses and society in general to have certainty about outcomes rather than perfect justice. If a plaintiff tries to dredge up old issues from many years ago it just wastes everyone's time and clogs up the court system.

That's definitely one of the reasons; evidence gets worse over time. Memories fade, witnesses die or become unavailable, documents get lost or destroyed, and physical evidence degrades. In this case specifically which is centred around a lot of discovery of emails and text chats, you can imagine that in other 5-10 years a lot of that discovery might become impossible to get and could drastically alter the outcome of the case.

It's also generally considered unfair for someone to have an indefinite threat of being sued or prosecuted hanging over them when their ability to defend themselves gets weaker over time. Limitations discourage strategic delays or using old claims as leverage far into the future. Without limitation periods, old business transactions could be reopened forever, estates could never fully settle, people and businesses would face constant uncertainty.

Ultimately, the courts are just better at resolving current disputes than reconstructing old ones.

Imagine if state could prosecute you for any tax fraud or mistakes in taxes past some years. Say 10 or 20 years ago. You do not have records anymore they have some. Seems like pretty hard to defend yourself in court. Same goes really into most matters.

If they were evading the police then the statute of limitations would not apply, because the case would stay active the entire time.

It is instead relevant if the state decides not to charge you for a crime but comes back to you decades later and goes "we changed our mind, now you have a week to come up with a defense".

You, hypothetically, are a bit of a rough person in your early 20s. You do some Crimes, one of which was against me. We'll say it was enough to give you a hefty fine and a year or less of jail time.

I don't press charges.

20 years pass. You grow up. You've changed your ways. You've become a squeaky-clean individual. You've put all that behind you. You become a healthy member of society. Your career's underway, you live in your own place, you may or may not have started a family.

Hey, remember that Crime I didn't press charges about at the time? Well, surprise, motherfucka. I've been waiting for this moment to do so. To the courts you go, get your ass fined, thrown in jail, and give you a criminal record, all so it'd hurt you that much worse now that you have your roots planted in your life.

Actually, you did Crimes to several people, right? Let's get them all in on this action! We'll just kind of trickle the suits in, one-by-one. Let one resolve, give it a few months, the next guy presses charges about his. Just kind of a steady flow of skeletons in the closet that you have to either defend against (and how are you gonna do that? It's 20 years old, hope you have evidence for your side somewhere in the attic) or take the sentencing of (which will do wonders for that career of yours), just to make your life hell.

Not a lawyer, but - fugitives don't get to run the clock on statute of limitations.

To a large extent.