All dogs, by around 10 months of age are showing their true personality and energy levels which they will continue to display up until the point that their body (usually due to arthritis) slows them down. Depending upon how routine your life is, most dogs will have begun to work out certain patterns in your life by around three years of age and will have appeared to calm down. Your dogs energy level is set at a certain age and will not get less, what will happen though, is that your dog will learn when to be excited and when not to be. Dogs work on routine and as they get older, they realise that there is no point being excited at certain times during a day. Interestingly though, when you enter certain parts of your routine, your dog will display exactly the same level of excitement, if not more, than it did as a puppy. In fact, depending on the dog and your routine, it is almost certain that some levels of excitement will increase as your dog gets older and understands your routine. Most dogs that are bouncy, excitable and difficult to manage at any stage in their life will likely continue to be the same until their body slows them down unless you take a proactive approach.