I can live easily without one !
I had one for years (good old nokia ... ) and changed it for a new one, the Ericson T28s at this time, and i didn't like it at all.
One day i sold it to a friend and i don't have one anymore.

Now i must say i'd need one, because i'm working in 3 different shops so sometimes it's hard to be at the right time everywhere i'd have to call ........ and for the kids too, i should have one to tell the person where they are if i'm late etc ... and she - or the schools - must have a number to join me if they need to.

So ... i think i will buy one soon ..... but really just for this sort of things.