Can someone, WHO REALLY KNOWS explain what updating the PRL does. As always, the web has conflicting statements.
Commonly heard around here is that it updates tower locations, so if a new tower comes on line, the phone won't see it until the PRL is updated. Not true
But most of the technical stuff talks about SYSTEMS (such as Sprint in area X), not towers, and these are only for roaming, not for home systems, the implication being that Verizon phones will pick up Verizon towers anyway, the PRL comes in when it needs to know whether to roam on a non-VZ tower. I believe that most of us do not roam in the US most of the time, which would suggest that updating the PRL isn't all that useful and is certainly not the first or second step to "fix" a problem.
But I can be convinced otherwise....
Just a quick observation, I hate PRL updates being offered like a fix for most phone issues and world problems.
Simply, a PRL update will update the partner providers and where they fall in the pecking order. As you travel around, if a VZW tower is not found, then the phone will look for an Alltel tower. If there is not an Alltel tower, then the next in line.... and so on down to towers where you would be roaming and have to pay for making a call.
If a new VZW tower goes live, your phone will see it automatically as the TOWER will be ID'd already as a VZW tower. However, sometimes a partner company may no longer have a reciprocal agreement with VZW concerning roaming, so the PRL is changed to place that company at the bottom of the list. But if you do not update the PRL, the company is still higher on the list on your phone and if you use them, you will get charged and the roaming indicator may not reflect you will be charged.
Most newer phones all update automatically now.