I have an underground fence. I have six acres fenced. Across the driveway it is buried about 4 inches other than that it just lays over the ground. It has been up for about 3 years with no problems.
I have no idea how they would work in a small yard but for our needs it has been great.
How well it works depends on training, the dog and the situation.
Training-
Its important that they don't associate anything with the shock like a leash or certain harness. When I brought my third dog home he associated the shock with his leash. All my dogs learnt what the beeping meant after one shock. Its also important to walk the perimeter with them where they wont get beeped at or shocked so they know where they can go and that it is safe. When the dogs are inside I take off their collars and leave them by the door.
In large part it depends on the dog-
My jack russell would not leave the porch with her collar on and she had only been shocked once. After a summer she eventually got over it, which it quite silly considering 6 acres are fenced in. She stays in the yard no matter what is going on outside her boundaries and doesnt try and go with us.
My labradoodle stays in the yard just fine no matter what is going on with the neighbors or outside his boundaries.
After a few weeks my husky learnt that she can just run though it so there is no point in using a collar on her. She knows where her yard is and rarely wanders but loves to go across the road (not a main road) to poop, I cant complain about that :)
Situations- Many pets have weaknesses cats, squirrels, moose, children, birds or other dogs. My husky learnt that she could simply sprint across by chasing a cat over the line. My parents dog cannot use an underground fence because he chases cars no matter what. They have tried an underground as well as a manual he really could care less. On the other hand the the jack russell and labradoodle will not cross the line with their collars on.
Once the dog has crossed they will not cross back over. My labradoodle inadvertently (only time it has happened) crossed over with our husky one day, she (husky) not having a collar on came right back over, he on the other hand was stuck. I had to go over take off his collar and show him that it was safe to return to the yard.
Longterm-
After awhile with the collars, the dogs do really well without them on. They know their boundaries and stay in them most the time. Our labradoodle rarely needs to wears his and the husky knows her boundaries. The jack russell is the exception she is the neighborhood busy body and will be long gone spying on the neighborhood without her collar. We leave the dogs outside when we leave and the collars keep them in the yard and from trying to go with us.
Overall, they work very well.
It really depends on the individual dog as I would never have thought it would keep our jack russell in.
It also depends on what you need it for. All we needed our fence for is to keep our dogs on our property and it has worked very well. We do get various neighbor dogs that escape from their yards and come over for a play date. The dogs seem to enjoy it and if I want the neighbor dog to go home I simply let all my dogs inside, it gets bored and wanders home.
You can tell if it is working, the box has lights on it that are on if it is working and other light that come on if it has been broken. For us its pretty obvious to tell if the collars are out of batteries as our jack russell will cross the boundary as we go to leave. They are easy to test, just take the collar off the dog and walk towards the line if it beeps its working.
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