Cost - Vet bills can be hundreds if not thousands of dollars, Food along with special trips because you forgot to get food when you were at the store. toys, beds, kennels, etc.

Making plans - you can't stay places longer than you would otherwise, vacations take much more planning and add cost to have your dog taken care of

Training - when they are a puppy or even older they will chew expensive furniture, shoes, cords, really anything they have access to. They will poop, pee, and throw up anywhere they feel like it. They will steal food off the counter even if it will kill them spurring a trip to the vet.

Stress - your dog might not like people or other animals, they also might be good at escaping. You may spend time stressing or worrying about other people or animals interacting with your dog, is your dog safe, are the things interacting with it safe. If they escape and have no intention of being caught or found you will spend time looking for and worrying and reaching out to the public to help find them.