Aside from raising my own pets throughout life (starting with rat tailed gerbils at 10, a snake at 11, a family dog at 16, my own dog in college at 19, outdoor/indoor rabbits at 25) I have also house sat for various friends as well as pet owners looking for help on multiple occasions as a child and as an adult. I don’t have any pets right now since I’m temporarily staying at my mother’s home while I’m in between jobs (I have the entire 2nd floor to myself so overnight dog-sitting etc is no problem). In terms of training, I have experience with big and small dogs, young and old. My dog in college was a perfect example. I raised him from just 6 weeks old in a hectic environment with 4 roommates and other dogs around often. He was a Rottweiler Pittbull mix but with my skill I raised him to be an extraordinarily well trained dog. By the time he reached maturity he didn’t require a leash (even if there is a squirrel in range) while walking him, he didn’t get aggressive with any persons or other dogs, he knew not to chew on human property/items, I could leave a plate of food on the couch next to him and go to the kitchen and come back without worrying, and this is all while there were other dogs around who should have been a bad influence since their owners gave them little to no training. Perhaps I was just lucky, but my close friends raised one of his brothers and one of his sisters who turned out horribly unwell behaved. I had to leave my dog due to personal circumstances after 4 years, but not a day goes by I don’t think about him like he was the son I never had.