It depends on the firm. Some legal and accounting firms offer 24/7 responsiveness to clients, and charge accordingly. Other firms provide work-life balance to their employees and make it clear to their customers that they won't be available after Xpm, or before Yam, and correspondingly charge significantly less for their services.

Moreover, the more-responsive firms compensate for the worsened work-life balance by paying their employees more. If employees would rather have work-life balance, they can always jump to a more balanced firm for a smaller salary.