And a maximum. Privacy laws also dictate that data should not be retained longer than needed for the purpose for which you're storing it. If you store data for statistics, a few days would be the max because you can count hits and anonymize data almost immediately. If you store data for the government and the government only needs it for 6 months, then after 6 months you have no right to store it anymore. And ISPs really stick to this.
And a maximum. Privacy laws also dictate that data should not be retained longer than needed for the purpose for which you're storing it. If you store data for statistics, a few days would be the max because you can count hits and anonymize data almost immediately. If you store data for the government and the government only needs it for 6 months, then after 6 months you have no right to store it anymore. And ISPs really stick to this.