Client wants to extend the stay very last minute, how should I handle this?

Rover can always help you extend a stay last minute. I to Even if you’re not able to modify the booking, you can call them and they’ll gladly submit it for you. I don’t understand why you’re wanting to charge a late fee/ that doesn’t sound familiar when it comes to pet care. If they go beyond the time they’re supposed to pick up, then a modification should be done to account for those extra service hours, which Rover recently automated

No, I don't see the need for a late fee. I do understand your frustration with the owner not giving you a solid answer but I think that in the future you need to be more assertive with the owners.

When the owners first said, "we'll let you know". I would of given them a time frame to "let you know by." Example: if you would please let me know by the end of the day (or a specific time) so I can plan your schedule accordingly.
Or please let me know by such and such time, as I need to let another client know weather I will be available or not.

Setting a client to have to give you an answer vs letting them get away with not answering you.

In the event they do say yes, I would make sure to modify their reservation. This way if they decide to change their minds at the last minute, you still get paid. (Depending on what your cancelation policy is.)

Best of Luck!

Rover has it that if it is more than half a day. It gets charged automatically. Even half a day gets charged half of what you charge. 20 would be 10, for half a day. If it is less it will not get charged. Do not worry and modify it first through the cat owner if they need more days.

Also cancellation policy is days before the 1st day you book so it is ex. on the 5th. You have 3 days before to cancel and put the new dates. 2nd to 4th