The pick, the radius, the ground.
Heaviest load, how far from the crane it has to land, and what the site is standing on. That chooses the all-terrain, the rough-terrain, or the boom truck.

Rough-terrain and all-terrain mobile cranes, boom trucks, and rigging crews for roofing, HVAC, steel, and precast lifts across the GTA and Southwestern Ontario.
Hoisting engineers. Toronto yard. Southwestern Ontario.
Roofing crews, steel erectors, and HVAC contractors setting rooftop units. More than 20 years combined. The machine is chosen for the radius and the ground, then it rolls.
250-ton mobile placing an HDT-80
Self-erecting crane set into place
Heaviest load, how far from the crane it has to land, and what the site is standing on. That chooses the all-terrain, the rough-terrain, or the boom truck.
Slings, shackles, and spreader bars for a rooftop unit ride on the truck. The plan is set before the crane leaves the yard.
Outriggers and cribbing level the machine before a beam comes off the ground.
Mast up, jib out, from its own trailer. No second crane on a tight urban lot.