How many of you have actually done the calculation to see what your 2012 tax liability would be? I am guessing not many. If you have not it may be a good idea to go through the trouble. Especially if you are not strictly a W-2 household.
If you find that you may owe money you may want to increase your withholding this may assist but you may also need to make an estimated payment by January 15th. Having more income tax withheld from your Dec. paychecks or IRA distributions can assist you avoid a penalty.
You can avoid a underpayment penalty so long as you prepay 90% of your 2012 tax bill; or by prepaying 100% of your tax liability for 2011. If you AGI was over $150,000 in 2011 you would need to prepay 110% if your 2011 tax liability.