Women's styles are more temperamental and under more scrutiny I'd guess. Women are judgey af amongst themselves.

Clothes are also a kind of costume. People wear costumes to elicit certain emotional pathways in the brain to prime you for performing the role that costume suggests. From a psychological perspective, trying on each outfit and fine tuning it is a way to prepare the mindset she is aiming for the day she plans on wearing it.

Guys' formal clothing is too uniform nowadays for us to engage in the same ritual, but all women will seek some level of uniqueness at formal events.