(TurboTax Online Free Edition customers are entitled to payment of $30.) This guarantee is good for the lifetime of your personal, individual tax return, which Intuit defines as seven years from the date you filed it with TurboTax. Maximum Refund Guarantee / Maximum Tax Savings Guarantee - or Your Money Back – Individual Returns: If you get a larger refund or smaller tax due from another tax preparation method by filing an amended return, we'll refund the applicable TurboTax federal and/or state purchase price paid.This guarantee is good for the lifetime of your personal, individual tax return, which Intuit defines as seven years from the date you filed it with TurboTax.