The regulation of internet and email usage in the workplace is of great practical importance for both employers and employees. It provides legal clarity and security: what is allowed, what is prohibited? The existing tension between the necessary abuse control and the risk of a transparent employee should be resolved through interest-based company agreements. The work outlines the constitutional requirements and examines whether individual claims based on established practice should also be considered when employees have been using IT systems for personal purposes for an extended period. In the discussion of whether tolerating certain behaviors can create an obligation for the employer, the work offers a completely new explanatory approach with the concept of tolerance authority.