I really hate that "lifetime warranty" very misleading, so warranty is only covered while being manufactured, once production stopped or supply runs out, your warranty gone, they may only make it for 12 months.
Usually lifetime warranty is that if the product you are trying to replace is no longer in production they will send you an updated version that is comparable in technology. By the time you want to get it replaced you already moved on to the next level of technology. I rarely have RAM replaced once its been working for over a year anyway.
@crisan_tiberiu Yes, actually. Like @Darkk said, if something is no longer being produced the company will give you the modern equivalent. This is one of the reasons why I buy Tupperware: some items that my mother had died after thirty(!!!) years and the Tupperware dealer replaced the item, which was no longer being made, with the equivalent product that Tupperware now makes.