See, this sounds reasonable but there are exceptions.

Today I downloaded an ISO file. It only got a cursory scan. If I want to know if something harmful lurks inside, I need to mount it and scan the contents manually. And yes I want to scan it before I try and install the program, because if I rely on the resident scanner I might end up with an aborted and botched install because Avast intervened halfway through, and it’ll leave me with a lot of manual cleanup of folders and the registry etc. So I’d rather know beforehand and not even bother starting the install.

On demand scanning definitely has it’s uses.

On the topic of the bell icon: If I could disable the bell, I surely would. It’s near useless.