Well, the answer depends. I always keep a screen protector on my laptop, but not for the reasons you may think. My Surface screen protector also works as a privacy protector, limiting the viewing angle of my screen, which is a huge help when I’m trying to get some work done in public. I don’t like the feeling of people peeking at my screen. If you haven’t seen one of those protectors, you can see a few examples here: https://viascreens.com/screen-protectors/microsoft/.
There are other types of screen-enhancing screen protectors that might be worth a look. And if you’d like your laptop screen to stay pristine and scratch-free for life, then you should absolutely invest in a protector. After all, it only takes a bit of sand getting in between the laptop’s keyboard and screen to potentially scratch the glass. And if you think you might end up dropping the laptop in the near future, they also make impact screen protectors that can help the screen deal with the shock without cracking.