This resource is part of a series of comprehensive guides on some of the most challenging components of ILF program implementation identified through extensive research and interviews with operating ILF programs and other mitigation stakeholders. These guides help address perennial problems for ILF programs by identifying specific challenges, providing detailed recommendations on ways to meet these challenges, and including examples or case studies of programs to illustrate effective approaches to implementation. This guide discusses challenges in applying a full cost accounting approach and outlines recommendations to help ILF programs ensure credit fees collected are sufficient to complete projects that offset the program’s mitigation obligations.