I’m aware of Valve being very generous with warranty/replacements of controller hardware for the Index. Even years after the warranty is up. But I think this is because of the major durability issues and known defects that the Index Controllers have.

In any case, Valve seemingly has lost money on a certain percentage of Valve Index kits/controller hardware. Based on how many people I know, including myself, who have gotten replacement hardware from Valve. Sometimes many times for recurring issues.