General pet-sitters are the wrong shortlist
A sitter who is excellent with dogs may never have noticed the early signs that matter in a rabbit, guinea pig, or hamster — the untouched hay, the smaller droppings, the animal sitting hunched in a corner it never uses. For a pet with existing medical needs, start instead with specialist small-pet boarding, vet-nurse pet-sitters, or experienced owners of the same species, and be specific about what 'medical needs' means in your case: daily monitoring, a strict diet, recovery from recent treatment, or simply a fragile animal who cannot miss a change. Ask directly what experience they have with your species and listen for specifics, not enthusiasm.
Interview with scenarios, not questions
Replace 'Are you good with rabbits?' with situations. What would you do if he refused his evening feed? When would you call my vet rather than wait until morning? How do you keep a pet's medication routine — as directed by your vet — on schedule when you cover several animals? A capable carer answers with thresholds and actions: appetite loss in a small herbivore is same-day urgent, records get written at the time, and your vet's number is used early. Vague reassurance, or any suggestion they would adjust the vet's set amounts or improvise treatment themselves, ends the conversation; administering care exactly as prescribed and escalating fast is the whole job.
Insist on a trial before the holiday
Book a short trial — a day visit or single overnight — well before the real trip. It tests the things references cannot: whether your pet eats in that environment, whether the carer follows your written schedule when you are not watching, and whether their updates tell you what you actually need to know. Supply everything for the trial exactly as you will for the holiday, including your written routine and emergency details, so gaps surface while they are still cheap to fix. A pet with medical needs who will not eat away from home may be better served by an experienced sitter in your own home; the trial tells you which. The trial also reveals the carer's reporting habits: you want measured, factual updates — what was eaten, what the droppings looked like, how the pet behaved — sent without you having to chase. A carer who goes quiet during a one-night trial will go quiet during a fortnight's holiday, and with a medically fragile pet, silence is the one outcome you cannot accept.
Hand over records, not reassurances
Write the handover as if the carer knows nothing: the plain facts they need — what the condition means day to day, what normal looks like for this individual, the exact routine your vet has set, warning signs specific to this pet, and your vet's details with written authority to seek treatment. Include recent weight and what a meaningful change looks like at this animal's size. Leave more food and supplies than the trip needs, in case your return slips. Assembling that history, routine, and record set into his KinsLe Pet Passport gives your holiday cover one complete packet to work from, rather than your verbal summary of a complicated pet.