Anything that breaks from the final product. So it's up to the companies to decide how modular they make their products. If it's not to modular, then if anythin

Anything that breaks from the final product. So it's up to the companies to decide how modular they make their products. If it's not to modular, then if anything small breaks, then they'll have to replace entire big pieces. If their devices are super-modular, then they will have to replace only that small part. But of course they also have to make all sorts of different small parts, or have contracts with companies that do.