Back in the 80's, I was service manager for a local A/V retailer. One day the sales manager told me that we were going to offer FREE LIFETIME picture tube warranties on all TV purchases, to compete with a large regional retailer. When I pointed out the cost of CRTs and the folly of such a warranty he refered me to the fine print.
When a customer has a problem involving the CRT we could, at our discretion, replace, rejuvinate or adjust the CRT. The warranty was a 1 shot deal, could only be used the one time, then it was over.
Of course I always put in a new CRT, but 99% forgot they even had a warranty.