To help avoid this, you can insert a digital timer into your PowerPoint slide to let the audience know exactly how long it will be before you begin. You could set the timer for 8 minutes, 10 ...

Learn how to make or create a Countdown Timer in PowerPoint. You can also use an Add-in. Displaying a countdown timer in your PPT can be helpful in many ways.

Launch PowerPoint, if you haven't already. Click "New Slide" on the Home tab. Click on the "Insert" tab and choose "Text Box." Click and drag on the slide to draw the text box.