After 2 years the battery usually start to pregnant, is better change if already pregnant, it won't hold charged for long after pregnant.

I change mine 2+ year once. Alarm will be longer because is not under hot sun.

Convenient always have its price.

I also seen some uses old car battery as a replacement, but it sit outside. Old Car battery may not be good for car but still hold enough juice for autogate.

Arm type autogate cannot be push because it use something like worm gear, it basically will lock the entire arm if no movement on motor, hence for these type of autogate have to remove the lock on the edge to remove the entire arm and push the gate.

You will notice arm have no locking solenoid like the old type (underneath) or DC motor, this because worm gear basically are very strong.

40, that more like China brand.