Life-cycle System Design
Life-cycle Asset Management studies the annual funding levels needed to maintain infrastructure in a sustainable way. Engineers have to answer such questions as: What do we have and what is it worth? What condition is it in and what do we need to fix it? When do we need to do the repairs and how much is it going to cost?
Life-cycle - the time from when the infrastructure was built to when it will have to be replaced.
Sustainable Development - "development that meets the needs of the present without compromising the ability of future generations to meet their own needs." American Association of Engineering Societies