Another method used by preachers to limit notes is to memorize part of the message. Here the preacher takes a manuscript, but has a particular portion of the sermon that is to be preached without reliance on it. For example, there are some manuscript preachers that know their introduction so well that they do not refer to their manuscript during this portion. Others like to memorize the conclusion/celebration so that they can close strong. Still others have stories or poems or even scriptures that they memorize to help in their presentation of the Gospel in the sermon.
This method will require less time to in memorization than memorizing the whole thing, and it can be very effective. If a preacher knows the key points in the sermon, then to memorize the presentation of those points can be almost as effective as memorizing the whole thing.
The drawback is that it can be kind of jarring to bounce back and forth between notes and non-notes. However, truth be told, many preachers who use a manuscript do bounce back and forth between their manuscript and notes-free presentation. Many do this very effectively. I would suggest that those who do this, take some thought in the preparation of the sermon which parts may be done without notes and which parts may have totally new additions due to the Holy Spirit’s editing function in the preaching moment. Then make note of these in your manuscript.