Linux noob here. Usually in Windows if I have a 1TB SSD, I make a 250GB partition for Windows and all of its things and I use the rest for a second partition where I install my stuff and store my files.
Usually in case Windows decides to go belly up, I still have my files. In more than 20 years it has never happened but I've always done it like that. I mean if Windows goes bad, I can still remove the drive and insert it into a different PC and copy my files away.
Should I shrink Partition 3 and make another one? Or keep it as it is? If I would, I read that I need to boot with a live usb to be able to shrink it. What kind of partition would I make?
I wouldn't use multiple partitions anymore. First of all, you would have to decide how large your home and system partitions are which can be annoying later if you either want to install large programs/games on your system or, say, download large videos into your home partition. Apart from that, SSDs life span is reduced if you partition them, because the controller then can't distribute writes across the while disk, so the cells will not get worn out uniformly.
The SSD write distribution theory sounds plausible but do you have any sources on that?
I wouldn't be surprised if SSD controllers distribute writes across partitions, transparently to the OS; if I was an engineer designing these things that's how I'd do it.
Unfortunately I haven't got any source. I read that many years ago, so it's very possible that modern SSDs behave like you suggested.
I'm pretty sure you're right