Defining the Time Horizon Sustainable development as a concept implies forever this may be impractical to deal with and can even lead to a feeling of helplessness. There is some merit in seeking to develop programs that are sustainable in perpetuity but such programs may require huge amounts of resources and considerable time for their implementation. It may be wiser and more effective to undertake a less demanding series of phased programs that initiate movement in desired directions rather than delaying action until longer-term programs can be put in place.