Yes Guided Access is great. I default it to a 20min timeout. So if I let my 8 year old play Minecraft on it, and he runs off to some corner of the house to binge, I don't have to worry about hunting him down. He'll get a nice warning around 3min out, and then the phone will essentially brick itself. It's great knowing that he will absolutely be coming back to me with the phone in 20min.