We have to be aware when the word "that" is omitted -- which usually makes something a dependent clause, needing no comma, rather than an independent clause, which would need a comma.
...Suppose a patient arrives on an afternoon and you've been in there in the morning.
No comma before "and" because the "that" is understood, beginning a dependent clause, not an independent clause.
...I know that Mr. Smith has drafted a lawsuit in this case and it's got a petition in it and the petition has sort of the legal crux of what the case is.
Happy punctuating!
Margie
