GSP, GWP and other sporting breeds like them (Weimereiners etc.) are extremely intelligent and have very high levels of energy. As such they get bored easily and as I tell all my clients a bored dog is a destructive dog.
I advise people constantly (literally every day) NOT to get a sporting breed if they aren't either hunters or very active people (hiking, running, biking etc.) and are able to keep their dogs working and moving. Two things can happen - your dog will get bored and start chewing, scratching etc. on everything and ruin your home and/or they will get fat which in turn is unhealthy for them - cardiovascularly AND for their joints.
This is especially true of pointing breeds like the GSP and their cousins. These dogs were bred to run and seek out game. I've watched pointer trials where the judges had to ride horses to keep up with the dogs as they ran the course and found the game to point. This could mean literally miles of tracking and running. If you can't give the dog this kind of exercise don't get the dog because it'll turn out bad for both you and the dog.
This isn't just about pointers though. Labrador Retrievers, Golden Retrievers, Springer Spaniels etc. are all touted as being great family dogs but they too can become bored and destructive. They are also capable of getting overweight easily and that takes a toll on their health.
Sporting dogs are working dogs. They were bred with high levels of energy and with a drive to run and hunt. If these basic needs aren't satisfied you will end up with a dog that you won't be happy with - a source of aggravation that you'll regret having gotten. I'm sure everyone has seen photos and/or paintings of a sporting dog sitting calmly at the feet of their master in front of a fireplace or just laying on the ground next to a chair... what isn't seen in those pictures is that in such dogs the owner has probably invested thousands of dollars into training and works the dogs on a daily basis - giving them an outlet for their energy. Then at the end of they day they can be found calm at the feet of their masters.
Now while I only mentioned sporting breeds other breeds are not well suited for sedentary life styles too - herding breeds and livestock protection breeds are one group that comes to mind.
There ARE breeds of dogs that are well suited for sedentary life though. A mastiff or other variations thereof is a good house dog - sure they're large but they are actually very low energy dogs and being not as intelligent as the sporting, herding and lsg breeds they are less prone to being bored. The drawback is that they are a little slower to train but still are trainable. There are other breeds out there that are well suited for being a house pet too.
Oh and just a note - small dogs aren't all necessarily great house dogs. Terriers for example are VERY high energy and have a high prey drive. They may be small but they can become very destructive too.
Now back to your basic question - whether or not to get a GSP. I'd suggest you take a look at your lifestyle and your family's lives. If you're not going to be able to let this dog get in lots of exercise and also keep it mentally stimulated so it doesn't get bored I would not suggest getting it. Just being a hunter doesn't mean your dog will be well suited for you either. You have to get him/her out moving EVERY day, rain or shine, warm or cold. Obviously in less than good weather you can take it easy and do less outdoors but we're still talking about a lot of exercise and a big commitment in time and effort on your part. Proper training is also absolutely required. Sporting breeds that have not been properly trained will become problems - running away for long periods of time, chasing after everything that runs across their path (and being gone for long periods of time), jumping up on people (and possibly knocking them down) and of course just not listening and minding what they're not supposed to do. I will say now that most people do not know how to properly train a dog, especially a sporting breed.
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