For instance, today I was told by a colleague that every day has a specific colour that you should wear according to her culture at least... and before i forget them, here they are:
Monday: White
Tuesday: Red
Wednesday: Green
Thursday: Yellow
Friday: Blue
Saturday: Anything but black
Sunday: Tend to red, but any colour will do

Well, I suppose the help from the above will be as follows:
1. It will help any wardrobe problem. youll know what colour clothes u need to buy for one! and that will help ppl like me stock up on colours other than blue!
2. dressing problem: Your choice will be limited, hence deciding what clothes can be worn for the day!! Definitely makes the morning getting dressed for office ritual easier!
3. The colours more or less compliment your mood. I mean white on Monday will calm you, and tuesday when your still grappling with a monday gone by u have energising red...and so on... with sunday giving u free reign.

Disadvantage:
Youll need a dress of these primary few colours
It will be pretty monotonous to see the same colour all around you on a certain day!