Patent annuities are usually due yearly in order to maintain a patent. The costs associated with renewing a patent are two fold; Official fees (taxes) required by the government/authority maintaining the patent and professional fees for the law firm or agency which is following up the patent annuity charges. Easy Patents charges between USD100 to USD250 depending on the annuity you are settling and depending on the country. Official fees range between USD30 and USD3,500 also depending on the country. Refer to costs for each country.