As devices go, smartphones and tractors are on the opposite ends of the spectrum. And an owner of a chain of mobile-device repair shops and a farmer of corn and soybeans do not usually have much in common. But Jason DeWater and Guy Mills are upset for the same reason: DeWater can no longer fix the home button of an iPhone, and Mills is finding difficulty fixing the newer John Deeres.

DeWater and Mills have more and more company. It includes not just fellow repairmen and farmers, but owners of all kinds of gear, including washing machines, coffeemakers and even toys. All are becoming exceedingly difficult to fix — which has given rise to a movement fighting for a “right to repair.” The movement has already managed to get relevant bills on the agenda of legislatures in a dozen states, including Nebraska.

Some types of gear, such as photocopiers and medical equipment, have always been hard to mend. But what has been the exception is now becoming the rule, said Nabil Nasr of the Rochester Institute of Technology. Even a John Deere tractor comes with millions of lines of software code, controlling everything from the engine to the armrests.

In their defense, firms said that restricting repairs, whether by individual consumers or businesses, helps protect their intellectual property and works on behalf of buyers. If Apple alone can replace the home button, for example, it is to stop hackers from getting familiar with the system that reads people’s fingerprints to unlock the phone.

Yet the lack of repairability has large drawbacks. Authorized dealers are often far-flung, much more expensive than independent ones and often cannot fix a problem. Barring owners from tinkering also limits innovation. Many inventions in farming equipment, such as circular irrigation systems, were pioneered by farmers.

And not being able to easily mend a device, said Mark Schaffer, a manufacturing consultant, contributes to a problem that already plagues many markets, as more products, from smartphones to washing machines, are thrown away rather than repaired, adding to waste and pollution.

To reverse the trend, but also to defend its industry’s turf, the Repair Association, a lobby group funded by repair shops as well as by environmental organizations and other charities, is proposing the “right to repair” laws that would require firms to provide consumers and independent repair shops with the same information and parts they make available to authorized service providers.