There’s an expression among responsible dog people : A dog is for life, not just for Christmas
As a writer, I would refine that to: A dog is for the whole book(or series), not just for temporary impact. To maintain reality even in a fantasy story, dogs have to eat, drink, and eliminate. Young dogs in particular need frequent and energetic exercise or they will exercise their teeth on the furniture corners.
Unless they’re trained to silence, dogs bark when surprised, whether that surprise is squirrels, terrorists, or invading zombies. They also whine at the most inappropriate times, in particular if they want you to provide the water, food, or a place to eliminate. The whining can escalate quickly to a wide variety of sounds (OUT!!! NOW!!!!!)
While our heroes are out saving the world, someone better be dropping by the house to tend to the dog, or there will be an unholy mess to greet said hero. Not to mention a mad scramble for OUT when the door opens.
Too many people acquire a pet as an accessory. They want a bright red colored dog to decorate their brown leather couch, but the dog becomes less attractive when that couch is replaced by a pink brocade love seat. They don’t consider the possibility of chewing or digging on that couch, or other inappropriate but very natural behavior, especially for a young dog. And far too many writers add a cute touch of whimsy with a tiny pocket sized dog to give their characters a bit of fashionista, forgetting said pet during high speed chases or sidewalk stumbles. Not to mention intimate romantic moments. Nothing like a cold nose or muddy paw to change cries of ecstasy to shrieks of shock.
Yes it’s difficult to remember the pets that seemed so cute in an earlier scene. Doing so gives depth to your character and your story. When your readers include people whose lives center around animals, it will make you a go-to author.
And who doesn’t want to be that happy author?