Phone plans change frequently, and the plan you signed up for a few years ago may no longer be the best fit your carrier offers. Many people also pay for extras they set up once and forgot, such as device protection on an old phone, international add-ons, or a line for a family member who has since moved on.

Start by checking your data usage in your phone's settings or your online account for the past few months. If you consistently use far less than your limit, you may be able to step down to a smaller plan. If you have several lines, ask whether a different multi-line plan would cost less overall.

On the call, ask the representative to walk through every charge on your bill and explain each one. Request that unused features be removed, and ask whether any discounts apply to you, such as those tied to employers, autopay, paperless billing or military service. Make sure any change does not restart a contract or affect a device you are still paying off.