Never trust a single session.
Things improve drastically however if you spin up a second session and ask it to adversarially review everything that the first session produces (this goes for everything: not just code, but also design, planning, and explanations).
This works even better if you use models from different families to do so.
Problem is where to stop. Open a 3rd session? Are you sure the 4th iteration is mostly correct? Let’s try a fifth now…