First-time Indie Filmmaker: Most Catastrophic Pre-Production Mistake?

Hey everyone,

I'm an AD, and I'm gearing up to try my hand at directing my own short film, finally. I've been pouring over tons of advice about pre-production, and there's a recurring theme of pitfalls, everything from incomplete breakdowns, neglecting shot lists, to really poor sound planning. It's a lot to take in and frankly, a bit overwhelming. I’ve been trying to be super meticulous with my schedule and breakdown, but I keep wondering if I’m missing something critical.

From your experience, especially with first-time indie filmmakers, which of these common pre-production mistakes tends to be the absolute most catastrophic on set or in post? I want to make sure I'm prioritizing my efforts on the right things.