Auto warranties seem good but most others are ripoffs with so many caveats and exclusions to make them worthless. Here's a few:
Delta Faucets - lifetime warranty but you need the receipt and you need to have filled out the product registration card. A plumber installed the faucet, I have a record of that, its supposed to be lifetime warranty anyway. Also who fills out produt registration cards for faucets? (They did send some parts to fix the faucet).
Gutterhelmut - lifetime warranty and service - the installer never returns my calls, they didn't tell me when installed it that they had choices onhow to install them and they did it in a way the installer has to remove them if a new roof is put on. They also cause ice damns in the winter - the warranty is worthless.
Roof warranty is worth as much as your tire warranty.
Anderson Windows - lifetime - there is a website with a form you have to complete. No response from them yet.