I only put a comma, sometimes, not always, when I feel like the successive clause could stand in its own sentence.
I only like to talk about the weather, and to go onto a monologue about the great person that I am.
but sometimes I also write it like this:
I only like to talk about the weather and go onto a monologue about the great person that I am.
So is it a mandatory thing. I believe there was a similar thread about comma before and, but the answer seemed to mention the Oxford style, which is when we put a comma between various listed elements and not clauses.