Every day! If you can introduce me to someone that know’s everything there is to know about their job then I’d be very surprised. There’s always something new or different to see in my job so I like to take the chance to learn something about it.
Not knowing something isn’t a bad thing, what’s important is realising that you don’t know it and then being brave enough to ask questions or get help. That’s the best way to learn and people will always be happy to help you.