If one knows they are about to undertake a medical treatment which could affect fertility (through surgery or medications), then freezing eggs may be worthwhile as the risks associated with freezing may override the risks of having future fertility problems.
There are risks associated with falling pregnant when one is older and these include higher chance of genetic problems (e.g. down syndrome) and miscarriage/still birth. These can be partially overcome through using frozen eggs when one was younger, but can also be screened during the pregnancy to allow parents to make an informed decision in relation to the pregnancy.
Most medical practitioners indicate that risks generally increase anyway after puberty. but substantially increase after the age of 40.
The other complication of waiting for a later pregnancy is conception/fertilisation rates lower. While there may be a higher rate of a fertilised egg with a frozen egg (IVF), the is still age risks associated with the fertilised egg not implanting in the womb.
Irrespective of whether frozen or ‘fresh’ eggs are used for a later pregnancy, the risks of gestational diabetes, placenta previa, breech positioning of the baby, emergency cesarean delivery, postpartum haemorrhage, preterm birth, low birth weight, high birth weight or mother mortality increases. There would be no difference between frozen or fresh as these complications are due to the mothers age and not that of the egg.
There is also the ethical dilemma of what to do with the frozen eggs when they are no longer needed. So they be destroyed. donated or used for research? Each of these do require some thinking as one will have to make a ‘difficult’ decision at some stage int he future.
I personally think that unless one knows of a major event (e.g. surgery or medications) which will significantly affects one fertility, the benefits of freezing eggs at 30 aren’t warranted.