Like babies, puppies need constant supervision. However, you also do not need to give your puppy access to all parts of your home.
Until he knows the house rules, confine your puppy to an easily cleaned area where you can keep a watchful eye on him.
Gate or Crate
Puppy gates are available at pet-supply stores; simply place them in a doorway as you would a baby gate (they work for puppies, too). Or buy a properly sized crate for your dog; especially if you plan to travel with your dog, a crate is an excellent idea. Think of it as your dog's home kennel, or an indoor doghouse; dogs generally see their crates as their personal space and, with training, will willingly go there on command.
To be on the safe side, until you know your puppy's jumping and wriggling abilities, remind everyone in the household to close doors to rooms with temptations like open wastebaskets and low toy bins. A New York couple came home one afternoon to find their Jack Russell puppy happily exploring an off-limits room; he'd learned to jump over the gate in the doorway.
Rooms to Avoid
It's not a good idea to confine your untrained puppy to the bathroom, garage, or yard. In the bathroom, she may be tempted to drink from the toilet. Beyond the fact that the water is unsanitary, there's the danger of her falling in and drowning, and the water can contain a harmful bowl-cleaner residue. Your garage is probably full of potentially lethal substances like antifreeze and insecticides. And the yard is dangerous to a curious puppy, not only because of swimming pools, fishponds, poisonous or spiky plants, and gardening implements, but also because of wild animals (large or small), birds of prey, and sharp twigs (remember, puppies love to chew!).
At Floor Level
To get a puppy's eye view of the areas of the home where your new pet will have free access, get down on your hands and knees. Whatever you see that's within reach, assume that your puppy will want to taste.
Some puppies will chew on anything and everything; others are more selective. One Brooklyn family thought their puppy hadn't chewed anything for weeks -- until the day they noticed that the lowest bookcase shelf had a row of tiny teeth marks in it!
Puppies are also great at wriggling into improbable spaces. So for at least the first few days, you may want to block off areas, like under a couch, where they could get stuck.