Every year Federal Individual Income Taxes (Form 1040) and/or the required Foreign Asset or Bank account filings (FinCEN or IRS Form 8938) must be filed in the US.
When to File Form 1040:
If you file on the calendar year basis, the due date for filing your return is generally April 15 of the following year. (April 15, 2016 for calendar year 2015)  If the due date falls on a weekend, the due date for your return will be the following regular workday.
If you file on a fiscal year basis (a year ending on the last day of any month except December), the due date is 3 months and 15 days after the close of your fiscal year.
If you are a U.S. citizen or resident alien residing overseas, or are in the military on duty outside the U.S., on the regular due date of your return, you are allowed an automatic 2-month extension to file your return and pay any amount due without requesting an extension.  For a calendar year return, the automatic 2-month extension is to June 15.
When to File FinCEN or Form 8938:
FinCen: Received by the Treasury Department by June 30, 2016 (no extensions of time granted)
Form 8938: By due date (April 15, 2016), including extension (June 15, 2016), if any, of your Form 1040 individual income tax return.
Filing Requirements for FinCEN or Form 8938:
 
  
Form 8938, Statement of Specified Foreign Financial Assets
FinCEN Form 114, Report of Foreign Bank and Financial Accounts (FBAR)
Who Must File?
Specified individuals, which include U.S citizens, resident aliens, and certain non-resident aliens that have an interest in specified foreign financial assets and meet the reporting threshold
U.S. persons, which include U.S. citizens, resident aliens, trusts, estates, and domestic entities that have an interest in foreign financial accounts and meet the reporting threshold
Does the United States include U.S. territories?
No
Yes, resident aliens of U.S territories and U.S. territory entities are subject to FBAR reporting
Reporting Threshold (Total Value of Assets)
$50,000 on the last day of the tax year or $75,000 at any time during the tax year (higher threshold amounts apply to married individuals filing jointly and individuals living abroad)
$10,000 at any time during the calendar year
For assistance with filing your Form 1040 or the FinCEN, we have an American former CPA who is qualified to prepare these filing for you.  Please contact us at ustaxes@4expats.cz to set up an appointment.

Useful documents: