A couple of points to ponder:
1) Do you ever do exactly the same speech twice?
2) Do you ever have identical audiences in the same few days?
If the answer to the second question is "yes", then the answer to the first could well be "yes". In any other circumstance, my answer to the first question would be "no". Every audience is different, and times change too. For me, that means I have to change my speech every time. I may use some of the same stories, maybe even the same opening and closing lines, but there will always be something tailored to the listeners and something that acknowledges current events. I may completely change the content of a speech with the same title from one day to the next, depending on who I'm speaking to and what's going on in the world.
The needs of your audience are paramount. They will be the arbiters of your success or failure. Their interests and drivers should be in your mind every time you create a speech. How much customisation do you do?
Photo Credit: Alan Stevens