We have one in the back yard. It's a PetSmart brand unit with matching collar. I use their wire, HD can order it online for cheaper than a pet store will sell it. Works for us, but it works for this dog because it runs around the outside of our 6' wood fence. Any breaks need to be repaired with sprinkler quality waterproof wire nuts. Anything less will eventually cause the controller to go crazy. You should not have to "check" for breaks, the controller should alarm because it has to have a continuous loop. If your controller does not, you need a better system or the controller is damaged.
We have to keep Rusty at least a couple of feet from the fence and any tree close to the fence. Yes, the 45 lb half boxer/half kangaroo/half ******* dog climbs trees. When I run it under ground, I only run it an inch or two. The rest of the run is on the lower back board of the fence, closer to collar level. With the collar on 4, which is one step below a phaser on kill, he will still run through if he feels the urge. And yell and flop like you shot him. Idiot dog. But it keeps him in the yard with the gates closed and nothing near the fence that would give him a way to get to the fence without sounding the collar. He self trained well and very quick. Wife asked me if we needed to train him, my response was "As much money as we've spent over the years trying to keep that squirrel legged ******* in the yard, let him figure it out." And he did, much to our amusement. We're both going to dog hell.

We did re-run the wire this year so it would go around the new shop and Rusty could come in and be a shop dog. The other little spare dog doesn't escape and causes no trouble except for shedding like a ball of fuzz.
We also have a bark collar because he's a loud SOB sometimes. I call him idiot, but the damn dog knows which collar is on.
I did read a review online from a person that told about their German Shepard. That dog figured out to sit near the fence with the warning beeper going until the battery died, then walk away.