It will never be unnecessary.
There is always failure of the most failsafe systems: I suffered one using an IUD, and had to abort, since my high BP and other health problems would have killed me or left me a stroke victim, and Richard with 2 boys and a baby... and a brain dead wife.
It not ever something one wants to deal with, but I won't let anyone say that it doesn't happen unless one is careless or doesn't care....