We let ours out all day with a dog door into the laundry room and also they have a room with cot sytyle beds in the garage with a dog door so they can go in and out.
In the old house, we had a 6 foot wood privacy fence that was smooth inside so no real worries there. In the new place, we were only allowed to install a vinyl picket fence that was 44 inches (3 feet 8 inches) high. Unfortunately, we were lied to originally about this (they said we could have a 6 foot privacy and there was one all along the road installed by the builder) and did not find out until it was too late when we got a revised copy of the covenants which said houses can only have the 4 foot privacy.
Anyway, after we were going to pull out, they offered us a decent sum of money off the house and we paid about $2500 to have holly bushes installed all around the backyard so that the dogs could not get a running start and jump the fence. Also, we did get them to let us put in a 5 foot section on the back where it rolled off and we could not find a 44 inch fence panel so we went with 48 inch.
At any rate, no problems, but ours have never been climbers. We took some time off and my wife worked from home so one or both of us were there with them for about 2 weeks all day after the move. I admit I was worried sick about it and had an electric fence system ready to go and even had an outlet put in a weird but conveinent place behind the back of the garage to power it, in case it was an issue.
So far no problems at all and they definitely cannot get to the fence with any kind of speed to get over it, but they do run in between some of the bushes and up and down the fence line. They actually get quite the game of hide and seek going. Before the houses behind us were done, we had driven behind ther eand looked at them laying on the deck and they go in and out all day when we are home and they do love it.
Here is a picture that I have. I was not meaning to show the fence (someone decided the table was a good spot to sit ), but you can see it and the bushes in the background. The bushes have grown probably 6 or 8 inches sine this was taken.