A crown usually requires 2 appointments and there is a temporary crown in place during this time. The temporary crown is designed to be removed with relative ease, so sometimes, it can fall off or break too early!
The biggest reason why people don't see the dentist as often as they should is because of the pain. If trimming our nails hurt as much, I'm sure many people would be walking around with 10cm long fingernails and shoes with extra long toe sections!
I remember I lost my retainers only after 3 days of getting them! I was in Carlingford Court (a local shopping centre) and took them out to have a coffee and cake. They were wrapped in tissues and I just left them on the table after I had finished. The workers obviously thought it was rubbish and threw them out..