It’s a good idea to evaluate your cell phone plan regularly. Maybe your carrier changed its prices, or maybe you changed your usage.

Running through this short checklist before switching your cell phone plan will help ensure that you don’t end up worse off — and that you’re getting the most value out of the plan you end up on.

Often, when a carrier changes its plan structure and pricing, it will allow customers to keep their old plan, sometimes indefinitely. (Verizon is trying to pry some of its old unlimited data plans from the 1% of its customers still grandfathered into them.) If you’re locked into a defunct but valuable plan, think hard before switching; you won’t be able to go back.

Also, check on the status of any promotional pricing you’re receiving. That will likely vanish as well.

The average cell phone user pulls down only 2 to 3 gigabytes of data per month. Obviously, if you’re paying for more than you use each month, you’re wasting money. But beware: With some companies, such as Verizon and U.S. Cellular, data overage charges might wipe out any savings you get from switching to a smaller plan. Make like Goldilocks and choose a plan that’s just right.

Don’t live with your family? No problem. If you know people on your same carrier whom you trust to pay their portion of the bill on time, jump on a family plan together. It’ll save you all money, as long as you’re willing to manage the logistics.

Set clear expectations for who is paying the bill and when everyone’s money is due. If it’s your name on the bill, be aware you might get stuck covering for someone else’s late payment.

Always check your carrier’s “deals” or “promotions” page, plus its recent news releases. Some new promotions are open to existing customers and should be easy enough to get on, although you might have to add a line to your plan.

Other promotions are open only to new customers, but don’t let that stop you. Call customer service and see if the company will give you the promotional price just for being such a great customer over the years (of course, you’re a great customer, right?). Or play hardball and tell the rep you’re thinking about leaving for a competitor — unless the carrier can sweeten the deal. It might not work, but it’s worth a shot.

Stephen Layton is a staff writer at NerdWallet, a personal finance website. Email: slayton@nerdwallet.com.

The article 4 Questions to Ask Yourself Before Switching Cell Phone Plans originally appeared on NerdWallet.