Back in the day, you could set a site, have the webserver write whatever log, and not worry about it. Whether you used for access statistics, or forgot about it and deleted, nobody cared.
Nowadays, depending on the legislation of wherever you live, there might be requirements for a minimum amount of information you need to log and preserve for a minimum amount of time, and restrictions on what information you can't log and need to remove after a certain amount of time, or upon request provide to users, delete, or save apart.