I believe money should be spent up front to save on maintenance over the life of your landscape. This approach underscores Total Cost of Ownership.
Dirt removal—where elevation is above grade or highly infested with bindweed, I recommend dirt removal, adding back in new material. Yes, you can use dirt to create berms from excess soil, but soil adds up quickly over large parcels. Mulch at 1 1/2" below concrete hardscape reduces the need to sweep pathways and improves walkability. I recognize that this often poses a risk to hitting sprinkler lines, especially if they were buried too shallow during initial install.
Versatile decomposed granite—DG is exceptionally versatile as it can be used for plants, walkways, and home perimeters. Exceptions: where there's large amounts of volume (in/around downspouts) or weed infestation.
Rock sparingly—rock is useful for erosion control, bioswale/water drainage, or driveways. Rock holds water in crevices, encouraging weed growth. When you use rock, choose the size for the job. If you have trees, interlocking large rock is easier to leaf blow.
Clean hardscape lines—I underscore clean hardscape lines where materials such as decomposed granite don't blend (low maintenance approach) with other materials except where edging would obstruct vehicle access. Using a single material for entire landscape looks beautiful, but often practical from a maintenance perspective: "one size doesn't fit all."
Sprinkler lines at 12"+—So that you can freely use a shovel to remove weeds and elm trees, install lines deep.
Tall edging for mulch—8" metal edging is expensive, but it's worth the cost long-term because it minimizes mixing of decomposed granite and mulch (aka maintenance). Additionally, tall edging enables 3-inch thick mulch, which suppresses weeds at a higher degree.