Usually one every 5 or 10 years. But the last years there’s been more

Nope. You fan register your number at different agencies to get messages directly instead of ordinary email. So if it’s from a court or law enforcement, it’s usually a letter to pick up the letter.

If you ignore it they’ll usually send someone to serve you I think. Or maybe fine you if it’s not super important. Not sure.

In Sweden, If it’s important mail with legal concerns, you’ll get a letter or an SMS that you have a letter to pick up at the nearest service point. The same way as you pick up a parcel. When you get I, you’ll have to ID and sign it, then it’s considered delivered to you.