Why does it change? In my experience most people keep their first cell phone number for their entire lives. Area codes are indicative of nothing, except where you lived in 2005 [1].
I live in Europe, and I've had 4 different phone numbers in the past 3 years.
* If I lose my phone, I've permanently lost my number. * Long-distance calls are a lot more expensive (about 5-10x as much). * Switch companies? Number lost again.
I've had about 5-6 mobile numbers since during the last decade.