In Cleaner professional why so many
Microsoft Visual C++ 2008 Redistributable - x86 9.0.30729.17
Microsoft Visual C++ 2013 Redistributable (x86) - 12.0.30501
Microsoft Visual C++ 2015 Redistributable (x64) - 14.0.24215
Microsoft Visual C++ 2015-2019 Redistributable (x86) - 14.23.27820
What do they all do and do I need them all ?
Where are you seeing them in CCleaner - I assume in the Uninstall list?
YES you need them all. (Probably).
Different apps use different redistributables, and so removing any one of them could cause an app to stop working.
You may also find the same one but at different version numbers, eg.
I say 'probably' above because it is just possible that one of them was only needed by one particular app that you have since uninstalled, but how would you know which one?
They don't take up much space so best to just leave them alone.
I think most people would agree though that it can be puzzling/annoying to see so many listed.
See this article from 2017, it asks the same question and explains what they are and why you have so many:
Thanks nukecad WALTER GLENNWALTER 6 MIN READ explained it .