What are the cost saving factors to design Drip Irrigation System?

I designed drip and sprinkling irrigation systems long time ago, and may allow myself to assert that the best use of the land topography (in other words; the land slopes) is a major cost-saving factor in irrigation systems generally.

i think the major factor is the design, and the quality of the material as the high quality material doesn't causes a lot of problems & dosen't need to high cost to fix and repier, only Regular maintenance will be needed.