I have a desktop application that has the ability to automatically update itself on the next restart (without the user's consent - but this is another issue altogether). Assuming that the user would never notice anything related to application updating (such as a progress bar, or pop-up requiring restart), and that our server would support the request spam load, is there any reason why it should not check for updates in less than 20 hour interval?

The reason I'm asking this is because all applications that I know that have auto-update capability check for update every 20 to 24 hours and at startup. I was just wondering if there was an ethical rule about it, or simply because of the risk of overloading the server.