Sayyiduna Abu Talhah (may Allah be pleased with him) narrated that when the Noble Prophet (peace and blessings be upon him) gained dominance over a people, he liked to stay in their land for three days.
He (sallallahu alayhi wa sallam) stayed there for three days so that the administration and management of the place could be properly entrusted to responsible individuals, and so that there would no longer remain any danger of another attack from the enemy.