If your employer is withholdingtoo much from your paycheck, oryou're paying more in quarterlyestimated taxes than you need to,you're giving Uncle Sam moneythat you could be using to build abigger nest egg. A sizable refundcheck should be a red flag thatyou're paying the government morethan you should. In 2001, nearly100 million Americans overpaidtheir taxes, with an average overpaymentof almost $2000. Use that$2000 to help fund your 401(k),and in 5 years at 6%, you'd havemore than $675 extra in your retirementkitty. Use the PaycheckWithholding Calculator at TurboTax.com to see if you need to file anew W-4. If you're self-employed,talk to your accountant about paringyour estimated tax payments.