Over the last quarter century, the U.S. Navy has bought over 6,000 Tomahawk cruise missiles, but fired only about 2,000 of them in combat or training. As the older missiles age, they must either be destroyed , or refurbished. The missiles are stored in a sealed container, which they are also fired from. Sensors monitor the state of missile components, and these are replaced as needed. But after a while, it's time for a refurb, or dismantling and disposal.
Lately, the navy has been refurbishing about 250 Tomahawks a year, at a cost of about $200,000 each. It's a lot cheaper than buying new ones. More recent models of the Tomahawk are equipped with sensors that report the status of many components, enabling missiles to be kept in shape with periodic maintenance and replacement of failing components. This does not eliminate refurbishment, but makes the process less frequent and cheaper.
Meanwhile, the latest version of U.S. Tomahawk (BGM-109 Block 4) missile, is getting upgraded so that it can hit moving targets. This is mainly intended to turn the Tomahawk into an anti-ship missile, although it can also hit moving land targets. Currently, the Block 4 Tomahawk costs about $1.7 million each, weighs 1.4 tons, has a range of 1,500 kilometers and carries a half ton warhead. It moves to its target at a speed of 880 kilometers an hour. Since production began four years ago, 1,300 have been made since.
The United States is developing a successor to the Tomahawk cruise missile, that will be heavier (2.2 tons, versus 1.4 tons), have a longer range (2,000 kilometers versus 1,500) and a one ton warhead (twice the size of the Tomahawks.) The new missile will be stealthier, and use a combination of guidance and targeting systems (to improve the chances of success). Price will probably be the key factor in whether this new missile ever enters service. The new Cruise Missile XR (for Extended Range) will probably cost twice that, or more. The cruise missile, when it showed up in the 1980s, was one of the first UAVs, it just wasn't reusable. But UAVs that carry bombs and missiles, and can be reused, are going to provide competition for a new, $3 million, Cruise Missile XR.