Dog boarding for more than 24 hours? Owner only booked one day?

Yes, in the future you should definitely charge more for services that are over 24 hours. Some sitters just charge a daycare fee, others charge for an extra night, it's up to you. Make sure you know when a parent is dropping off and picking up before you book so you can charge accordingly! If something like this happens, you can "extend the stay" via the app or website.

Since you already agreed, it might not be a best business practice to try to up the rate now. I agree that in the future letting them know that over 24 hours but under 48 hours is considered a boarding + drop in fee, daycare fee, etc.

If this particular client books again, just let them know your policy while setting drop off and pick up times

Since you've already agreed to the extension, without telling the client there would be an additional fee for the overtime, then you really can't do anything about it.

Normally, I'd say that you should charge for daycare, but I see your daycare fee is higher than your boarding rate, which is kind of unusual since boarding is for up to 24 hours of care and daycare about half.

It is certainly up to you how you bill. In this particular case, you originally agreed to an overage of 5 hours (11 am to 4 pm) without compensation. Dragging it on to 8 pm makes it 9 hours over, for a total of 33 hours (not 30) which is certainly daycare-worthy pricing.

You could send an "extend the stay" request to the owner and explain that the daycare needs to be paid before the pup can be picked up. Or you can just let it go this time and chalk it up to the learning curve.