I carry Airtags to my sits; one for each pet & an extra for the owner’s keys. (Long story on another thread about how useful this was on one sit!)
I also try to “condition” the pets by singing “Din-din…!” whenever I feed them. Depends on the pet & my length of stay whether they really pick up on this, but it’s something I can do proactively. I always it that with my own pets at home…you can feel the earth shake from the stampede to get back to the house, whenever they hear me sing it. 