Same here. I pay so little for my minutes anyway. And gosh, how smart would it be not to call a customer for clarification just because it's my own phone? I'll show 'em! I may drive around for hours, but I wil NOT call from my own phone.
The other day I was driving with my station's ops manager to pick up some rental trucks. He was drivng but making calls constantly. At UPS I was told never to answer or talk on a cellphone when the wheels are moving, and that still makes good sense to me. If anyone doubts this, go to YouTube and look up U.S. Dept. of Transportation videos about texting (and, I add, speaking into a phone) while driving.
I'd much rather be considered a professional driver who prevented a tragedy than one who killed a mom crossing a crosswalk with her baby because I was dialing a number.