When I first started preaching, I thought that I wasn't very spiritual if I used somebody else's outline or material. I used to think I had to have a FRESH word from God that I came up with all by myself. That kind of thinking is called arrogance and is borderline stupid :)! There is nothing new under the sun. Even preachers who say they don't use other people's material when they preach are fooling themselves. They use somebody else's commentary notes, Bible software programs, different versions of the Bible that they didn't write, internet resources or some other tool to help them put their messages together.
I will use somebody else's sermon, illustrations or outline in a HEARTBEAT. Of course, I make it my own. Sometimes, I hear a speaker say one sentence, and it triggers an entire message in my heart, but the original idea came from somebody else. Get over your arrogance and pride and use all of the resources that are available to you in the 21st century. It will take your preaching to another level!