EPO: European Patent Office
EPC: European Patent Convention
EU: European Union
Annuity: Annual fee required by many foreign patent offices to be paid to keep the patent application or grant pending.
Maintenance fee: Fee paid to the USPTO to keep a granted patent alive. The fee is due by the 4th, 8th and 12th anniversary of the issue date.
Renewal: Use this term when you are speaking about both foreign annuities and US maintenance fees.

When a patent application is filed under the EPC, the application is referred to as an EP application.

If you file an EU application, you will be filing a trademark or design application, and NOT a patent (utility or utility model) application :-).

Once an EP application has been filed, annuities must be paid to the EPO on the anniversary of its official filing date in order to keep it active. The EPO allows the annuity to be paid by the end of the month in which the anniversary falls, rather than the actual day of the anniversary. If you miss the initial due date, you can pay the annuity within 6 months of the actual due date – but with an additional late fee of 50% of the actual fee. So it can be paid late, but at considerable expense.

Try not to miss that final date, as it can be extremely difficult and very costly to resurrect the application (and is only possible under certain limited circumstances).

European applications can take several years before they are granted – I’ve seen them pending for over 10 years. As the annuity fee increases every year, it can get extremely expensive to just keep the application pending. As of April 1, 2010, the first annuity that is paid (usually on the 3rd anniversary of the priority date) is €420 (about $575) and the 10th year annuity is €1420 (about $1,950). These are just the actual fees due to the EPO – additional fees for the payment of the annuity are also normally charged by either the annuity service company or the foreign associate.

Note that the EPO allows for the filing of “Requests for Expedited Examination” – there is no official filing fee for this document but your foreign associate will probably charge you. Since the annuity increases each year, it may be beneficial for the application to be examined sooner rather than later, even if only to avoid paying the additional annuity fees.

(As usual, this is not legal advice, but practice tips.)