First I thought to myself, "I seem to use too many commas." Now I'm no writer, but I've noticed that professional writers (and editors) clearly use less commas than I do.

For example, here's a sentence in a book that I'm reading: “As the victim was usually unconscious it was obvious they were totally reliant upon third parties and whatever action they took would determine their fate.”

I thought it was interesting, because I would've put a comma after "unconscious" and a comma before "and."

So, I found this helpful resource on grammar rules: https://www.grammarbook.com/punctuation/commas.asp. 4a and 5b in particular were situations where I learned I could get rid of commas.

Still however, in the example sentence above, you'd think to put a comma before the "and" to separate the two clauses. I haven't found an explanation for omitting it, other than some writers are grammatically correct in a stricter sense, and others use commas more stylistically.

Is the use of commas more of an art, if you will, than I thought? How do you use commas personally?

Interested to read others' opinions!