I was wondering if php programmers keep error_reporting in php.ini on or off after delivering the website?
You should always keep on error reporting, logging of most important events and audit. Otherwise, the day your application will fail for some reason, you'll have a hard time to figure out what happened.
This being said, error reporting must be done internally, and never shown to the end user, since it would be a security issue to show sensitive information. You can use
By the way,
Another comment also tells you that: