Motors are very simple. The main thing that goes wrong in a motor is going to be the bearings. As long as you do not crash, and keep them oiled, they will last for a long time. I oil mine right after a day of flying. The rest of the motor is just wire and magnets, so as long as you keep the motor within operations range, the wires will stay fine. I think your ESC will go out before the motors will.
On a regular bases you should check every connection if you can, like ESC to motor wires, ESC to controller wire, battery terminals, GPS wires etc. Also inspect your props to make sure they are tight enough, but do not over tighten as you could crush the prop.
Here are some things I did to add to my safety margin.
I put a locking nut on each of my props.
I use two batteries in parallel so if a wire breaks, or a cell goes bad, I have a backup.
I solder all wires from ESC to Motor, do not ask how I know this.
I use hot glue on all of my servo wire connections from the ESC to the controller.