I am Yaron Eliya, and I have been diagnosing commercial gate systems in California since 2014. Here is what I see on high-use properties.
The gate shows one small symptom first. A grinding sound during travel. A half-second lag on the close cycle. An inconsistent reverse when the photo eye trips. The facility manager notices it, maybe logs it. But the gate is still working, so the call gets pushed.
Then the drive gear starts skipping under load. On a rack and pinion operator that is the pinion losing engagement with the rack. On a chain drive it is the sprocket and a stretched chain. Either way the rack or the chain begins to show uneven wear in specific spots, and the limit switch, the component that signals the motor to stop at fully open or fully closed, starts missing its mark. The gate overshoots, or it stops mid-travel.
Then it goes down during a delivery window at 7 a.m. Now it is an emergency.
When I arrive on a job like this, the motor board often shows heat damage from the drive forcing the motor to compensate for weeks of mechanical slop. A drive gear replacement that would have cost a fraction of the repair now includes a motor board swap.