When you’re giving a presentation in a predetermined time slot and you realize that, if you continue at your current pace, your presentation isn’t going to end on time, you have two options. You can either speed up your pace by talking faster or cover less content by focusing only on the most important remaining content.
The former approach creates stress, and that stress impacts not only your ability to communicate your thoughts but also your audience’s ability to understand your message due to simultaneously thinking about your frenetic body language.
The latter approach means that you don’t cover some content. However, by skipping the content that isn’t a priority, you can get the key elements of your message across, thereby retaining your calm and increasing the likelihood that your audience understands your message.
The reasoning outlined above regarding what to do when you’re pressed for time when presenting can be generalized to other contexts. Specifically, when you’re pressed for time, it’s better to do less by prioritizing the important things than to do the same amount by rushing through it all.