If you have more than one PowerPoint presentation, chances are that you can reuse a few of your existing slides in any new presentations. Perhaps you need to create a presentation on short notice or you just don’t have the time to devote to creating every slide from scratch (and who does). Even if you have all the time in the world, why would you want to work harder than you have to?  
When that design or data you need in a new presentation already exist, insert the existing slide into your new presentation instead of recreating it! Don’t scrutinize too much—a specific slide doesn’t have to be 100 % reusable. You can use pieces; it’s often quicker to revamp an existing slide than to create a new one.
If you decide that you can reuse existing slides, PowerPoint has a helpful feature called Slide Finder that will insert those slides into your new presentation. That’s right—you don’t have to copy and paste each slide. To use Slide Finder, open your new presentation or create a new presentation and then follow these simple steps:

  1. Make sure you’re in Normal view.
  2. Click the slide you want to precede the slide you’re inserting. This feature will insert a slide or slides after the selected slide.
  3. From the Insert menu, choose Slides From Files.
  4. Click Browse on the Find Presentation tab (the default) and then locate the presentation that contains the slides you’re reusing.
  5. Click the slide or slides you’re reusing and click Insert. Or click Insert All. If you want to insert more than one slide, but not all, hold down the [Ctrl] key while you click the slides you want to insert.

The process in considerably different in PowerPoint 2007:

  1. Click the slide you want to precede the slide you’re inserting.
  2. Click New Slide in the Slides group on the Home tab and then select Reuse Slides at the bottom of the resulting dialog box.
  3. Click the Open A PowerPoint File link in the Reuse Slide pane to the right.
  4. Locate the presentation that contains the slides you want to reuse.
  5. Click the slide you want to reuse or choose Insert All Slides.

Once you have the existing slides in your new presentation, you can use them as is or tweak them a bit. Reusing slides when possible is efficient and PowerPoint makes the process easy.