I don't appreciate "adlib" sermons as they usually don't work effectively. Unless the minister is extremely skilled, adlib sermons tend to ramble and repeat points without cohesion and direction, which dilutes or even loses the message intended. With only ten to fifteen minutes to get a clear and concise message across, sermons need to be thoughtfully prepared beforehand and edited carefully. This means writing them out, but not necessarily reading them from the pupit in a rote fashion. It is hard work, but since the sermon is the "heart" of the service, a necessary element of the minister's calling. Written sermons also provide the congregation present and those not present with an opportunity to further reflect on the message and/or provide feedback.