<prompt> Human: I had a trusted CPA file my tax return. She provided me with a voucher to send in the I owe the IRS. I had a unique tax situation in 2016 and the first quarter of this year that will not recur, and have never owed on my taxes before. I stupidly put the voucher and check in the regular mail on Thursday.Is it worth paying the 40 or so to put a stop on that check, and run by USPS on Monday to send a new check via certified mail? I still need to send in my estimated tax for the first quarter of 2017 so will be stopping by USPS before Tuesday anyway. Honestly I would have rather paid online, but Ive never had to file with a 1040 before and the online payment system was trying to verify my identity by finding past years self employment taxes, which I dont have. Do I need to cancel that check and resend certified, or am I being a worrywart?EDITED TO ADD: Maybe I am a worrywart, but Ive had USPS lose a lot of my mail in the past and Im not risking a 5 penalty for late payment. Today I put a stop payment on the check to the IRS which Ive confirmed will NOT incur a penalty even if the IRS receives and tries the cash the stopped check - see stop payment at and figured out how to pay what I owe online. Peace of mind is worth the 25 stop payment bank fee less than I had anticipated! Thanks, Chase! to me.  <response>: There how nearly everyone filed taxes until the last few years. Ive picked up dozens of letters to tax depts with just a simple stamp 