What if my family income changes after filing for financial aid?

The FAFSA application asks for your prior calendar year’s income and you can’t fill out the application until the year is over. So if you fill out your fafsa on Jan 15th or six months later on July 15th, your income from the prior year (in this case 2008) would still be the same.
So to answer your question, it can’t change so nothing would happen.

It sounds like your question is really asking about your marital status and changes you may have that. So here is the REAL answer to your quesiton. Your marital status is documented "AS OF "on the date you fill out the fafsa. So you can’t go back and update or change the information because as of the date you did your fafsa your marital status was correct.

If you got married after you did your fafsa, you would put yours and your spouse’s income. You could NOT go back and change your marital status to a previously filed fafsa because the fact you were not married on the date you filed does not justify a correction. You will have to wait until you do your next fafsa (with the next years income) to have those changes take effect.

It depends on what type financial aid you’re talking about. But, usually they go by your status on the date you complete the application. So, if at all possible wait till after you’ve gotten married to complete the application.