Over the years, we all have seen stuff like :
"HALP ME ! MAH GAME DOESNT WERK ! WHEN I LAUNCH IT, IT DISPLAYS AN ERROR MESAGE, SOMETHIN BOUT MSVCR120.DLL IZ MISIN ! I DOAN UNDERSTAND ! HEEELLLLLLP, OR IM GONNA HAS HART ATTACK !!!!"

This is because lots of programs (including games) make use of the microsoft c++ redistributable, commonly used files in C++ programming. So if you don't have this redist and the program you want to use needs it, the program won't work, obviously.
The thing is that there have been lots of versions of this redist : 2005, 2008, 2010, 2012, 2013, 2015, ...
And for each of these versions, several subversions exist. And sometimes, the redist get installed several times even for a same subversion !
Both for 32 bits programs (x86) and 64 bits programs (x64).
And all of these versions are not compatible with each other : having the 2012 version will be of no use if you want to run a program that needs the 2008 one...

This results in a mess and a lot of redist to install on your computer.
The good news is that starting from 2015, these redist are retro-compatible. So starting with the 2015 one, the redist will include the previous versions.
So if you install the latest (2019), it will include the 2015 and 2017 ones without the need to install them.
Moreover, installing the latest automatically uninstalls and replaces the previous ones starting from 2015.

So now, you no longer need to search for and install every single fucking one of them. Installing the very latest will be enough. Of course the old ones before 2015 are unaffected so you still may need to have them separately.

This will decrease the related troubles a bit, hopefully there will be less cases of "HEEELP ! GAME DOESNT WERK, I DOAN UNDERSTAND !".

Link to the latest redist as of now (2022) :
x86
x64

-------------

TL;DR : you no longer need every single MS Visual C++ Redist, starting from 2015 ; the latest will suffice.

Thanks for the info. I have some more info and a question to add...

1) (info) My old Xp system used have Symantec Norton AV. Whenever a game needed to install a C++ library I was asked to disable AV and "repair". It got so if a game was above a certain size (would probably need a C++ Lib) I just disabled the AV before installing.
The point here is some AV's won't give the message above, they'll just stop the C++ Lib installing. So perhaps check your AV before crying foul on GOG. (Not you Pouyou, I mean generally).

My current system is Win7 with Vipre and Malwarebytes. No problems with C++ Lib installs. Other than it happens so often - which brings me to...

2) (Question), showing my lack of tech here, but logic tells me that C++ Libraries are needed by windows. So wouldn't they be in the Windows folder when installed, and accessed by any game that requires them? Or if two games need the same C++ Library is it installed twice, once in each game folder?

They get installed to the System32 and SysWOW64 folders (all the msvcr1xx and msvcp1xx dlls).
Some programs include them in their own folders as well in order to avoid any failure, in other words, these are duplicates.

This is good to know. .............. are fucking retarded and make using windows as annoying as Linux.

Luckly we still have .Net for those cases...

Excellent. Thank you, this has been bothering me ever since the libraries were automatically added during the installation of Fallout 3 GotY and Fallout 3 New Vegas.

Welcome to Windows, where your hell is a lack of proper package trimming and a hell of dependencies.

Seriously, being able to trim the fat with sudo dnf autoremove is pretty sweet.

Lol, I nearly forgot about .net...does any game now still even use that stuff?

Many thanks Pouyou.

No, I think that for older programs, the 32-bits version should suffice.

I have checked and (with Windoze-10) not only are the obsolete libraries not uninstalled with the latest (2019) redistribution, but also earlier games (e.g., Full Throttle: Remastered) crash if one manually removes the earlier libraries. (Much as I'd like to blame Microsoft, presumably these earlier games have a hard-wired reference to the particular C++ library, rather than the specific procedure names, when they call a function.)

TL;DR Yes install the latest library but NO don't lose the earlier ones.