Women may want to freeze their eggs for medical reasons, e.g. they have been diagnosed with cancer or another serious illness, are about to undergo medical treatment or perhaps because they are at risk of early menopause. All these circumstances are likely to affect their ovaries which can prevent them from producing eggs in the future.
Single women or women wishing to delay childbearing due to career/social reasons may decide that they want to preserve their fertility at an optimum time in their reproductive life, in preparation for treatment later on. If freezing for social reasons it is advisable to freeze your eggs whilst you are younger in age as the quality and quantity of your eggs declines with age.