Where the acceptable range is genuinely narrower

Some advice aimed specifically at women in this subject is padding. Some of it describes real differences, and separating the two is more useful than pretending there are none.

What is genuinely different

The acceptable range is narrower, particularly in law and finance. Less latitude on formality, on colour, on expression.

That is an observable fact about how those fields read portraits rather than an endorsement of it, and someone navigating the constraint deserves to know it exists before spending money.

What is not different

The geometry. Contrast between hair and background, a crop matched to display size, frontal rather than side light. Those decide legibility for everyone.

The two wardrobe rules that apply regardless

Avoid fine patterns, which create noise at small sizes and interfere with compression. Avoid anything close in tone to the background.

And the thing worth remembering

At the size a professional headshot is usually displayed, none of the wardrobe detail survives to be judged at all.