Push me, Pull you
Clutch life is tied to wear, so if the clutch is not slipping, it is not wearing. Starting the load in the lowest gear possible is important because as noted, there is less slippage. If the driver wants to skip shift after staring the load (startability), that is acceptable, however starting in a higher gear is not recommended, unless clutch life is not a concern.
When does the manual clutch have to be adjusted? Reduced free play in the pedal is an indicator of when adjustment is required. Many new chassis utilize air assisted hydraulic linkage in an effort to reduce clutch pedal force in the cab. Only a mechanical linkage has free play, not the air/hydraulic assist. Therefore, it is imperative to call out the self-adjusting/solo clutch with hydraulic linkage. If not, the clutch adjustment can only be determined by pulling the clutch cover off the bellhousing, and inspecting the gap seen in Figure 2.
Trucks utilize pull clutches, so as the surface wears, the throw out bearing moves closer to the fingers on the clutch shaft. Eaton Spicer says there are 17 adjustments in a new clutch. Do the math to determine if a self-adjusting clutch is worth the added expense. Do not forget to account for the cost of downtime.