The dog does not care whose week it is. It still needs its walk, its dinner, and somebody to notice when something is off. When the kids are moving between houses and you are moving between two calendars, the pet sitter becomes part of the household routine, so treat the choice the way you would treat any other helper who will be in your home.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Start with the visit type
Decide what you actually need before you talk to anyone. A drop-in visit fits a pet that is fine alone for a few hours. A longer midday visit fits a pet that needs a walk and a meal in the middle of the day. An overnight stay fits the nights you are truly away. Ask each sitter which of these they offer and whether they do the same visit type every time, or whether a different person arrives on different days.
Check who holds the key
Ask whether the sitter will keep a key, where it will be kept between visits, and who else has access to it. Ask what happens to the key after the week ends. Some families keep a lockbox, some hand over the key at each visit, and some use a neighbor as the only key holder. Pick the arrangement you can explain to your kids in one sentence.
Ask for the written plan
A plan in writing is the difference between a good week and a guessing game. It should cover feeding times and amounts, walk length and route, where the leash and bags are kept, the vet's name and phone number, and what the sitter should do if the pet seems unwell. If your pet takes any medicine, decide with the vet's office what goes on the page and who is responsible for giving it. Do not leave that part to memory.
Find out how they report back
Ask how you will hear from the sitter after each visit. A short text, a photo taken at the door, or a one-line note on the counter are all reasonable. The right answer is the one you will actually read on a busy evening, not the most detailed one.
Ask about the backup and the cancellation line
Ask who covers if the sitter is sick or double-booked. A sitter who has a named backup is easier to trust than one who says they will just find someone. Read the cancellation line too. Know what happens if your plans change on short notice and whether there is a charge for a visit that was not needed. Ask in writing whether the sitter is insured or bonded and what that covers.
Compare two sitters on the same page
Write the same list for each sitter: visit type, key arrangement, written plan, reporting, backup, and cancellation. Put the answers side by side. Then book a short trial visit before the first split week, so you see how the dog reacts and how the sitter handles the leash, the door, and the questions your kids will have.