It’s up to you entirely. Neutering a dog is a sensitive issue and PETA will probably advise you against it. What they forget is that dogs are in constant contact with humans and live among us in our neighborhoods. As someone who owns dogs, the pros of neutering outweigh its cons, almost every time.
The major advantage of neutering is that neutered dogs are calmer. It's simply because of the drop in the testerone level of the dogs. The aggressive nature of dogs is decreased after neutering and if your dog is protective, it can help a lot. Breeds like pugs, newfoundlands and labradors can still be excused since they’re inherently calm. If you have a mastiff, pitbull or daschund, I would recommend neutering. Dogs that haven’t been neutered are not a threat to you, but to the people and dogs around you.
Neutering also makes dogs less prone to certain diseases and contributes to the overall health of your dog. It also helps keep your dog calm during heat and helps you keep your sanity. The major con of neutering is that dogs are more likely to get fat after neutering so make sure your dog gets plenty of exercise. Good Luck!
You should absolutely neuter your dog not just for their health but also for your sanity. I once spent almost a whole weekend without any sleep because my intact dog knew there was a female in heat down the road and he could not relax. He just paced up and down the hall almost non-stop for three days.
Neutering a dog can help prevent the dog from developing testicular cancer. And, so many unwanted puppies have to be euthanized that I believe it is just the responsible thing to do for your pet and for our society.