The sockets and ratchets did and may still have lifetime warranties, the power tools usually only one and I think occasionally two year warranties. Shortly after that repair parts start getting hard to find. Blades and bits would only be warrantied against defects. Once I got a blade that still had a raw chunk of carbide for a tooth. It got missed in the grinding sharpening process. You can't imagine what rough is unless you've had it happen. That would be an instant replacement. If a blade or bit vibrated so bad you couldn't use it it would be an instant replacement. Prematurely wearing out would probably be your problem unless a lot of people had it happen and made a big stink about it. So there are at least 3 levels of warranty. Lifetime, limited, and barely out the door.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.