Please hire a sound guy. I was going to end there, but I guess I feel the need to elaborate a bit. The vast majority of beginner film makers seem to underestimate the importance of quality sound recorded on set. The video itself is only half of someones experience when it comes to viewing the final product, and believe me, the average viewer is more susceptible to picking up subtle audio issues than you may think. They may not know why that voice sounded off, or why they just didn’t quite buy that location as being real, but the do notice. A great number of things can be edited and fixed in post, but your dialogue is of paramount importance, and capturing that properly on set will save you a world of headaches.
I’m not trying to point this out just so I can make a paycheck (but if you need a sound guy… Hi!), it’s as much an issue for me as it is for you. There is no magic “de-overmodulation”, “de-wind” or “de-gopro audio” button (my goodness gopros have terrible audio). I do what I can with noise reduction and spectral repair, but in the end you can either ADR it, which has it’s own multitude of issues (many actors do not like ADR and I can’t really blame them), or live with the audio you get. Specifically with documentaries, the second option is usually the only one, making sound guys even more important on docs.
With budgets continually tightening you can’t always afford to pay someone to capture your sound, you are probably often working for free or pittance yourself, so try to remember this: high quality location recordings are good as gold, and you might only realize this when it’s too late. If you can’t afford someone to monitor sound levels, do it yourself. Throw some headphones on, make sure there is no clipping in the audio, and for the love of God, do NOT point your camera mic at a refrigerator. Thank you.
Your friendly, and always affordable sound guy.