paragraph spacing

Space before a praragraph vs. space after a paragraph

Some would say space before and after a paragraph is a "you say tomato, I say tomato" kind of thing.

I run into situations where we have added space before and space after that accumulates and gets very confusing especially when one is designing a template of a complex document.

Bullets and numbered bullets are the worst.

Generally speaking is there a "proper use" for before spacing and for after spacing? I imagine if only one was needed, only one would have been provided.