I have some clients whose dogs I walk every workday, in one case multiple times a day (small dogs with small bladders). My loose practice has been to offer a 15% discount off my posted rate to regular clients who are booking three or more services a week. It's more efficient and easier to schedule for me to get weekly bookings from old clients instead of playing email tag and going on meet-and-greets that might or might not work out. From the client's point of view, it's a real financial burden to pay for pet care every day in order to go to work, rather than as a rare expense associated with optional activities like going on vacation or doing something in the evening.

I was wondering if other sitters do anything similar.

For the daily rate you mention, I will do bedtime walk through breakfast, and then make midday and dinnertime visits for walk, play and feeding. If the client requires that you be there essentially around the clock, thus foregoing other jobs and responsibilities, I would charge accordingly.

I am a service provider with money in my Rover account from services provided in 2018. If i leave the money with Rover until 2019, will I incur a tax liability this year or next? In other words will I get a 2018 1099 that shows the payment this year even if I leave the money in my account?