I strongly encourage and highly suggest tipping a sitter, especially on THS. I started doing this after three cancellations, and once I began letting sitters know upfront that a tip was possible, I haven’t had a single cancellation since. It’s a huge motivator.
I tip THS sitters who stay in my home for more than 8 days (my vacations are always at least that long). My minimum tip is $125 and it increases from there based on their performance & overall care as I explained previously!
Sitters also tend to communicate far better when there’s a tip involved 
I’m going to start a new thread regarding this topic. Would love to get other THS sitters and homeowners opinions on this besides just yours.