Well-run legal departments should have goals that have cascaded from corporate headquarters. A mission statement announces some of the durable goals, others might vary from year to year. A practice in a law department is a means to achieve one or more of those goals. To illustrate, a goal is to manage outside counsel responsibly, practices in pursuit of it are legion. Or a transcendent goal might be to steward corporate funds well.
David Hume, the great empiricist philosopher believed that our wants and desires determine our ultimate goals, and the role of reason is limited to telling us how best to achieve those goals. Reason applies to means (practices), not ends (goals). Emotional and psychological needs fuel goals, whereas the thinking parts of our brains, ideally, choose the tactics and techniques to get their.
If corporate goals are set for law departments, if the trickle down from on high sets the objectives, then managers of law departments apply reason to select among the contending methods to achieve them.