If you decide to add a second pet to the family, do so cautiously and slowly. It is best to allow the pets to meet in a neutral spot to avoid any territorial disputes. Some pets feel they need to guard their home and family. Bringing a new pet into the same space can cause problems if they are not watched closely.
The temperament in the pet you have, and the one coming into the family is important to think about. If you have an older pet, and the new one is much younger and full of energy, there could be problems with them adjusting to each other.
Whether the pet is male or female can make a difference when choosing a second pet. A neutered animal is less likely to have aggression problems. Is the new animal the same type as the one you have? You have a dog or a cat, and you want a second dog or cat. A dog may or may not accept a cat in the home. Two cats or two dogs may or may not get along with each other.
When adding a second pet into the family, do not forget about the one already there, this can cause problems. You should treat booth the same way and not leave them alone until you know that they will get along. Watch pets while you are near so that you can break them up if you have to. This is something to do whether the pets are new or have been in the family for some time. There may be some petty arguments from time to time. My pets do, but it happens less now than it used to. They are both male dogs.
If you are thinking about bringing a second pet into the home remember, let them meet in a neutral spot, watch how they interact, keep an eye on them, treat them equally, and there is a good chance that they will get along and become a great addition to your family.
Please consider a shelter for your new pet. Shelters are overloaded and you can save a life by adopting a shelter animal.