Upgrade your laptop yourself?

What should I put attention on? What can I upgrade?

Almost nothing just the fans

Don't build in anything that doesn't belong in there. But you could build wheels underneath. This increases the distance to the table and improves ventilation.

I'm just interested in not paying a surcharge of several 100 euro for more RAM

With a laptop you are relatively limited in contrast to the desktop PC… Look at https://www.pc-magazin.de/ratgeber/notebooks-aufruesten-85923.html or https://www.computerbild.de/...65449.html, you can't do much more…

That depends on the laptop.

With some you can't change anything, with others CPU, GPU, RAM, WLAN card and hard drive / ssd.

OK thanks. Could you give me a few models where this is possible?

With my Acer aspire V3 571g CPU, ram, wlan card and hard disk were possible.

With the CLEVO X170KM-G you can also replace the graphics card