When she runs out of space.
Like a hamster hoarding its daily supply of seeds and pellets to last it a lifetime, a woman keeps every article of clothing in her wardrobe. The big, the tight, the outdated and the small, she keeps them all for sentimental value and in the hope that one day, they will come back into style and she can fit into them. The tight jeans she has kept for three years, trying them on every few months but never quite getting into them because they are simply two inches too small, she puts them in the bottom of her wardrobe anyway. She doesn't like to admit that she's fatter than she would like herself to be. The sparkly minidress she never has had the courage to wear, she doesn't throw it away lest it might become a must-have fashion piece one day. The few tops that are too tight, she holds on to them hoping that one day, she might just lose some tummy fat and finally looks gorgeous in those tops.
With women's passion for shopping, it's a pretty safe bet to say almost every woman's wardrobe grows on a monthly basis. In a blink of an eye, the wardrobe becomes too small. Or to put it logically, the amount of clothes and accessories grows too large. The woman finds no other way to accommodate her precious properties but to throw away the absolutely useless. That's when she has to finally accept the truth that she is not committed enough to lose the excess two inches off her waist and that even when short sparkly dresses are in trend, she probably will never have the guts to put on one. Out with the misfits while the safe and comfortable wear stays.
Now that she has more space, the cycle continues.