This is a bit of a loaded question. In general, you must have received this income for 6-12 months. The lender must also be able to document that the income will continue for at least 3 years from the date of application. This can be done via divorce decree or other court appointed documents. Another thing to keep in mind is if this income is to be reduced during the 3 year time period, you would be required to qualify on the lesser amount. There are several exceptions for as little as 1-3 months, but each program is different. This is why it is critical to consult an expert early on in the process.
Scott Evans, CCIM, CRMS, founder of The Family Mortgage Team, which offers tools needed to easily understand and compare home financing and refinancing options. Visit his website for more information.