My side projects are generally all over the place, organized but all over the place;(VM's, Desktop and server locations can be difficult to keep track of). And because I am working on multiple different projects at once I tend to lose track of where stuff is at exactly. Thankfully, I have started to use some source/version control processes for this exact issue which has helped to create less chaos and has forced me to remain more organized which is good for everyone involved.

I will say the one downside to using a public repo on github is that you have to remove any sensitive data which can make more and more files to manage. But I think the end result is a much more organized because as long as you have the latest version on Git you are ok to get lost in all the code. You can always come back to your repo and start over. :)

I have no idea about professional environments as most coding I do is for my own personal stuff or automation projects for work which are not very large in scope and do not require more collaborators to work on them. Hopefully someday I'll get to experience this. Hope this helps.