Section 86.73 - How long must I operate and maintain a BIG-funded facility, and who is responsible for the cost of facility operation and maintenance?(a) You must operate and maintain a BIG-funded facility for its authorized purpose for its useful life. See §§86.3, 86.43 , and 86.74 .(b) Catastrophic events may shorten the useful life of a BIG-funded facility. If it is not feasible or is cost-prohibitive to repair or replace the BIG-funded facility, you may ask to revise the grant to reduce the useful-life obligation.(c) You are responsible for the costs of the operation and maintenance of the BIG-funded facility for its useful life, except as allowed at §86.14(b).