On most commercial roofs, the open field of the membrane is not where leaks start. They start where something comes through or sits on the roof: HVAC curbs, gas lines, pipe supports, hatches, and drains.
Every penetration needs its own flashing, and every flashing is a seam that has to be done right. When a roof is installed in a hurry, these details are the first to fail.
Service traffic adds wear. Technicians walking to and from rooftop units, dragging tools and dropping screws, slowly wear the membrane thin along the same paths. Walkway pads along those routes and around the units protect the roof where it takes the most abuse.
Supports matter too. Gas lines and conduit should sit on proper pipe supports, not directly on the membrane, so they can move with temperature changes without cutting into the roof.
A yearly inspection that focuses on curbs, penetrations, and drains catches small problems before they turn into wet insulation and ceiling stains.