In my opinion, if there is a cost, it must be extremely minimal. Professionals who own these devices could very well do tests after one, two or three years, depending on the features of the devices. It must be relatively easy to do. I am sure that the companies that manufacture those devices have included a system similar to that of a smoke detector, that is, if the battery is defective after a certain time, a signal is sent to change it. I haven't done a study on that, but I'm sure that, if you invite suppliers here, you'll find out fairly quickly. Today, there are more and more suppliers of those devices.
On June 12th, 2018. See this statement in context.