I have a friend which have a hoarding disorder when it comes to coding. Here are some of the things he does:

1: If he rewrites, remove, or in any other way refactor a function, then he keeps the old one in the file commented out.

2: If he deletes a class then he takes the code and paste it into a class that he have just for old code. AN ACTUAL CLASS! Not just some random text file somewhere. Even though it is commented out, he leaves it so that you can initiate his garbage.

3: In point 1, the code is not pasted on the end. It inside all the other actual code.

So if you try to help him with something, then you have to dig through a mountain of shit just to find some code.