I knew absolutely nothing about actuators of any kind until my son got a different car. Before he bought the car he looked at several different warranty programs because he knew he wanted an extended warranty on the vehicle.
It didn't take long for him to have to use the warranty. After only 3 weeks he was not able to lock his car doors. When he had it checked out, they told him the actuators in the door panels needed to be replaced.
The first thing he did was look at his warranty agreement to see if something like actuators was covered. Thankfully, it was covered under the electrical system.
Until he had this experience, I had never given any thought to what an actuator was or how it worked.