What if you haven't filed an FBAR for a very long time? There are three approaches:
Just file them - If you haven't been contacted by IRS and you have already reported any income associated with the accounts on your returns, your best bet is to simply file your FBARS with your trusted FBAR-filer. When submitting the FBARS - you or your FBAR- filer will give an explanation of why you filed late to avoid penalties - most commonly - "ignorance of the law." Simply filing the returns - might be the best approach but you might also consider...
The "Streamlined process" (waiver of penalties, but doesn't close door on criminal prosecution). With the streamlined process, first offered in 2012, you show the IRS that there's no willful conduct. In this procedure, you don't pay a penalty if you are overseas and a limited penalty if you live in the U.S. However - this program seems a bit over-glorified and quite complex.
OVDP program (to avoid criminal prosecution)
If you not only didn't file FBARS but failed to report interest or dividends from these accounts on your 1040 tax returns: you should probably come clean thru the OVDP (Offshore Voluntary Disclosure Program) whereas you disclose the fact on not filing FBARS AND not reporting the income and you avoid criminal prosecution in your presentation. Your FBARS and amended returns get submitted together with a request for leniency, etc.