If the government owes you, you'll lose your refund if you don't file within 3 years of the April tax filing deadline date.
This means that for tax year 2014 returns, you'll need to file by April 15, 2018 to claim your refund (October 15 of 2018 if you filed an extension).
On the other hand, if you owe taxes, you'll be subject to the failure-to-file penalty, which amounts to 5% of your unpaid tax bill for every month your tax bill remains unpaid after the April deadline, up to a maximum of 25%.
In the meantime, the IRS will send you several reminders to file. If ignored, the IRS may then file a substitute return on your behalf. And while
this may sound like a clever way to hand off your tax-prep chores to the government, keep in mind that government-prepared returns may not grant you every deduction or credit you're entitled to.
Delinquent taxpayers who owe more than $25,000 will eventually receive a visit from an IRS representative to collect payment.
Are you self-employed?
To receive Social Security credits towards your retirement, you must file within three years of the original filing deadline, whether you owe or not.
This means that for tax year 2014 returns, you'll need to file by April 15, 2018 to receive your Social Security credits (October 15 of 2018 if you filed an extension).
Don't lose your Social Security benefits by not filing!