What is their experience?
This should be your #1 question. You want someone who will know when an emergency is dire or can be waited out until you get home. They should also know the signs of, and how to break up a dog fight. You don't want someone whose only experience with dogs is that they love them and had a family pet growing up. Bonus points if they are going to school for, or work/ed in veterinary medicine.
what times they are available to check on your pet?
The potential pet sitter should be willing to work with your pet’s regular routine and come at the specific times you request. Don’t be too strict and ask them to be there right at the 15 mark, but give them up to an hour before and after to get to your place. Also, check if they charge extra for early morning or late night visits. Don't forget a dog should be let out to go potty at least three times per day minimum, preferably four!
are they insured?
A responsible company will be fully insured and have that information available to share with you. If they are an individual sitter working alone, at least get a copy of their driver’s license. I have had so many owners ask to make a copy of my ID and I am always more than happy to provide it for them!
are they comfortable with your dogs and their breed?
Always, always, always have the person come by and meet your pets first! Check that your animals like and feel comfortable around them. Bonus points if the sitter owns or has specific experience with your breed or mixes. I’ve been to many dog shows and have met and worked with (on some level) almost every single breed in the U.S. Owners really loved this and found comfort knowing that I wasn’t a stranger to their Afghan Hound/Coton de Tulear/Nova Duck Tolling Retriever and so on.
are they okay with your list of instructions?
If you have a sitter who negatively reacts to specific instructions you ask them to do - such as administering medications, run. They should be taking excellent care of your pet, that’s literally their one job.
Do they have good reviews or referrals?
If other people seem to have good things to say about the sitter, then they probably are trustworthy and can take good care of your dog. If the dog sitter or company has even one negative review… don’t be afraid to reach out and ask both the owner and sitter what happened in that scenario to get both sides of the story. Sometimes it could be something as trivial as the owner being upset the sitter charged a holiday fee. Just makes sure to ask and get as much info as possible!
I could go on and write a novel about what to look for in a good dog sitter, but here is a good place to start! Don’t be afraid to ask lots of questions and openly communicate any concerns or specific requests with your potential pet sitter before hiring them.