DH years ago had a personal cell, and gave it out for office phone calls. They quickly ran through our rate plan, so they offered to get him a work cell, which he agreed to.
So he got rid of the personal cell and used only the work cell, but then in some lame cost-cutting measure, some staff members were getting spoken to about their personal calls on the work cell. (Not DH, his calls to me were like once a day and very brief, but other people had a lot of calls and long ones.)
So from then on he's always carried a personal cell and a work cell/Blackberry, and never the twain shall mix.