You will need to be more specifc in your question. So to "generally" answer your very "general" question: Women will wear what they know to wear, what they feel like wearing and what they can afford. Media will detemine the trends and we like mice... follow along.
Like lemmings to the cliff.... we all race towards the fashion abyss only to fall and land on what we all know... basic black works in all circumstances and for all reasons and seasons.
Casual - Black jeans, black or white shirt or sweater, add an accessoriy and you are simple ... FAB!
Evening - who doesn't know the basic and simple... little black dress? An all time classic... STUNNING
Day wear - basic black suit - power dressing to the MAX.
Mommy wear - black just doesn't baby throw up or baby goo. Mommy SMART!
Kids wear - Black doesn't show dirt!
Fashio lesson....dress like the Addmas Family... have fun!