How much notice do you need for a cancellation?
For pet sitting during a trip, as much time as possible. It's problematic for me to turn away business for work that then gets canceled at the last minute. For walks, there isn't as big of a time commitment so it's not as critical. I can almost always be reached by text during the day in case something comes up, though it's possible I could arrive before recieving the message. If last-minute cancellations become a regular issue, other arrangements will need to be made.