This is something business first learned a long time ago. In the 19th century, when organized labor first compelled factory owners to limit workdays to 10 (and then eight) hours, management was surprised to discover that output actually increased – and that expensive mistakes and accidents decreased. This is an experiment that Harvard Business School’s Leslie Perlow and Jessica Porter repeated over a century later with knowledge workers. It still held true. Predictable, required time off (like nights and weekends) actually made teams of consultants more productive .