I have never liked to preach a sermon twice. Unlike people who carefully record and store every sermon, if I have notes I throw them away as soon as I get home. This isn't because I don't think it is right, but because I have found it hard to get excited by an old message.
There are, however, some parable sermons that I re-preach and are settled in my mind so I don't need much preparation. I was surprised to find how well one was received when I used it a couple of weeks ago (and I expected people to find it a little shallow!)
And then we have a church service every Wednesday evening during Lent and I have been sent to a different society in Mitchell's Plain every Wednesday. Being a bit hard up, I decided to just use the same Lent sermon each time - and again it seems to be well-received.
I am challenged to think that re-preaching sermons may actually be a good and useful thing!