In reply to Frank4short:
This is the wording from Gore's website:
<quote>
GORE-TEX® Fabrics Guaranteed To Keep You Dry®
If you are not completely satisfied with the waterproofness, windproofness, or breathability of our GORE-TEX® outerwear then we will repair it, replace it, or refund your purchase price.
If you find any reason for complaint, you should first of all return to the store where you bought the item. Retail stores that sell our products want you to be satisfied just as we do. They will tell you what to do in order to have your garment repaired. The guarantee is applied to all GORE-TEX® garments that carry the GORE-TEX® Guaranteed To Keep You Dry® logo but it depends on the condition of the garment.
The policy is to make an individual judgement based on normal wear and tear to the garment compared to obvious failure in the manufacturing.
The guarantee will also follow the domestic legal consumer recommendations for returns.
</quote>
Note the comment about wear and tear vs manufacturing defect. To me, this says it's a reasonable guarantee that the fabric will be free from manufacturing defects. It doesn't say that you can have a new jacket when you've worn the old one out.
Personally, I think that Gore-tex is a triumph of marketing. This is not to say that it doesn't perform. For many years, it was the best you could get. I'd say that it isn't today.
I say that it's a triumph of marketing because it's pretty clear that most Gore-tex consumers don't really care about breathability. If they did, Gore would be seeing a huge number of returns once people had washed their garments as per Gore's instructions, which recommend the use of detergents. Once you use detergent to wash any DWR, you negate its effect, so the garment wets out, and bang goes the breathability; you can't pass water vapour through a layer of water.
So, why do Gore insist on specifying detergent for cleaning? My only conclusion is that they believe customers want an easy-care solution, so the use of domestic detergents is the easiest answer. This can only mean that most customers don't really need or understand the breathability issue.