Funny I came across this today, as in a few months I will be house/dog sitting for friends of a friend in Hawaii. If they have plants to water, I will be happy to take care of those, too.
Payment has not been discussed, and frankly, I don’t expect to be paid, nor would I accept payment if they try to offer. I didn’t intend to have a Hawaiian vacation this year, so it’s not like I was going already and needed a place to stay, but since the offer was presented to me, I will take it! I will be saving a ton of money on hotel, restaurants, rental car, etc. so I don’t expect to be paid on top of that.
If they left me a bottle of wine, or a restaurant gift card, I might use it so as not to offend, but it certainly isn’t expected. I like pets, I like Hawaii, and I think my being able to stay there and enjoy a vacation and use their place and car while doing so is more than enough payment! While I am gone my mother will be house and cat sitting for me, and I will likely leave her some gift cards and a fridge full of groceries since she is retired and on a fixed income.
If I were the original poster, I would reach out to the house sitter and say…hey, we probably should have talked about this initially, but in your mind, are we trading our house for your sitting/watering services? Or do you want to charge us something for taking care of the cats and plants? Email if that is more comfortable than asking in person.
One last note…I am very invested in my own pets and also run an animal welfare organization. There are only certain people I would completely trust with my cats. I have seen too many horror stories where the pet sitter lost the pet. Make sure this acquaintance is one who can be trusted! If they feel put upon because jeez, now they have to take care of your cats when all they wanted was a place to stay, they might not be the best choice. Good luck!