One valley, several growing conditions
The east bench sits higher and cooler, holds snow longer, and is shaded by mature trees in the older neighbourhoods. The west side is more open, warmer through the afternoon, and windier. The same watering schedule and the same mowing height will not serve both well.
The soil is the common thread
Most of the valley sits on heavy, alkaline soil left by Lake Bonneville. It compacts under foot traffic and under a season of irrigation, and once compacted it sheds water rather than absorbing it. That is why core aeration does more for a Salt Lake County lawn than it would in sandier ground.
A short, decisive autumn
The window between the heat breaking and the ground hardening is narrow here. What happens in that window — aeration, a late feeding, getting leaves off the grass — is what a lawn looks like the following April.