It pays to check over your monthly bills. I know this and tell other people to do it all the time.
You never know when you might find an error, computers make mistakes.....you know the drill. In theory, smart consumers know to check their monthly bills for mistakes.
In practice, it doesn't always happen. And I admit, I had gotten kind of lax about it.
So when I happened to check over our cellphone bill the other day, I was at first mystified - then horrified - to discover we were being charged $10 per month for a data plan on one of our phones.