Adding a second puppy is a TON of work, at least for quite a while. Having two adults, not so much, depending on what you want to do with them... but the first many months is a huge change. Making sure both dogs get training and exercise time separately, monitoring their together time when the pup is smaller, being on top of the puppy 100% of the time when they're not crated... it's a lot of work. If both dogs will be sport dogs, that crazy level of works continues into adulthood. If not, then it sort of mellows out. The dogs I have right now, the adult is a pet only while the puppy is a sport prospect, so the adult doesn't require nearly as much work and training.