Which one should you choose? It depends on the laptop and what you want from it. A fanless MacBook Air or any thin, low-power machine is fine all day long, and you can even buy stands for just that. If you’re running a gaming laptop or any workstation that gets really hot, leave it on. And if you’re not sure, check the manufacturer’s site to see if it’s happy to run under load with the lid closed.
If you are going to be closed, there are a few things worth doing. Keep the power adapter plugged in, because the laptop draws more power with an external monitor connected, and you don’t want the battery to quietly drain in the background. In Windows, open the control panel and look for it Choose what makes the closing of the lidthen set both cover options Do nothingor the laptop will sleep the second you close it. Put it on a stand to allow air underneath, and don’t count on a cooling pad to do much; the temperatures only slightly lower and do not cool the gap between the screen and the body.
There is also a middle road. Close the lid just far enough to turn off the screen, but not all the way, and as long as hot air isn’t blowing directly on the screen, it should be fine indefinitely. It doesn’t keep the dust out, though, so plan to clean the laptop every so often.
Overnight jobs are the easy case. A render, a large download or an old laptop acting as a home server can all run with the lid closed as long as the fans are clear and the work is light to medium. Heavy loads are a different story.
If you keep it open, the tips are easier. Give the laptop some room for air to move, keep the fans clear and if it’s a gaming laptop, tilt it on a stand.
One tip works for both approaches: Get a docking station. A good one removes the keyboard, mouse, power cable, HDMI and audio, so the laptop only needs one cable to connect to all. When you want to take the laptop somewhere, you take that one cable out and go, instead of dragging five. Most also keep the laptop tilted so there is room for air to circulate.