Clearing all calendar entries or all contact details in a book
If testing then needing to refresh data, it can be helpful not to have to delete the book, but rather to be able with an option onscreen (with safeguard confirmation!) to empty it of all contents/records, before importing a fresh set of content. This saves re-doing synch-ing for a book, sharing, settings changes etc.
The way to do this is to create a new addressbook/calendar and then deleting the one that you want to empty, but you are right. Sharing has to be set up again in that case. With proper clients you shouldn’t have to touch any sync settings – the new one will just show up on configured devices.