(17)To ensure that the investment firms’ order execution policy remains effective over time and adequately reflects market developments, investment firms should assess the effectiveness of their order execution policy at least annually. Investment firms should also do that whenever the monitoring of the order execution policy indicates non-compliance with the order execution policy or the requirements laid down in Article 27(1) of Directive 2014/65/EU, or whenever any material change in the cost, price, speed or likelihood of the execution and settlement, or the size or nature of an order, or any other parameter relevant to the execution of the order affects the ability of the investment firm to continue to obtain the best possible result for its clients as referred to in Article 65(7) of Delegated Regulation (EU) 2017/565.