I always discuss before the owner leaves what he expects from me. I always ask the pertinent questions as a very experienced sitter. You have the responsibility to make it clear what you expect from them. Every pet owner has different expectations.
You are totally right. It’s really important that an owner realise that they are being given a service for free. So they are not technically a paying customer. In this situation I find voicing requests to be important and then if the sitter agrees, that sets the bar. I personally did not enjoy being asked daily for updates - that ruins my experience of enjoying my time in the property (the value exchange I receive as a sitter) as I always feel like I am working. 2 times a week after an initial first day update is reasonable (assuming all is well). Beyond that, that leans into a paid arrangement for me. Most HO I have worked with don’t expect more than a weekly update. Everyone is different.