When auditing a company's implementation of IFRS 15, auditors should pay attention to several key considerations. Here are some of the most important:

1. Understanding of the Standard: Ensure a thorough understanding of IFRS 15, including its core principle and the five-step model for recognizing revenue. This understanding will help when assessing the company's revenue recognition policies and practices.
2. Review of Contracts: Auditors should carefully review contracts with customers to understand the terms and how they impact revenue recognition.
3. Identification of Performance Obligations: Assess the company's process for identifying performance obligations in contracts with customers. Auditors need to verify whether the performance obligations are properly identified and separately accounted for.
4. Transaction Price Determination: Consider how the company determines transaction price, including the treatment of variable consideration and significant financing components.
5. Allocation of Transaction Price: Review the company's methods for allocating the transaction price to the identified performance obligations, and whether this allocation reflects the standalone selling prices of the goods or services.
6. Revenue Recognition: Understand when and how the company recognizes revenue, i.e., over time or at a point in time, based on the transfer of control to the customer.
7. Management Judgments and Estimates: IFRS 15 requires significant management judgments and estimates. Auditors need to evaluate these, including judgments made to determine standalone selling prices, to estimate variable consideration, and to assess whether performance obligations are distinct.
8. Internal Controls: Assess the effectiveness of the company's internal control over the revenue recognition process.
9. Disclosures: IFRS 15 has extensive disclosure requirements. Auditors should verify whether the company has complied with these requirements, ensuring users of the financial statements have sufficient information to understand the nature, amount, timing, and uncertainty of revenue and cash flows from contracts with customers.
10. Transition: If applicable, consider how the company has managed the transition to IFRS 15, including the method of adoption chosen and how the impacts on the financial statements have been communicated.

These considerations allow auditors to evaluate whether the company is in compliance with IFRS 15 and whether its financial statements fairly present its financial position and performance in accordance with the standard.