We have been worried we were going to have to buy new windows. Several of the seals on our double-pane windows seemed to have broken (seen by moisture in the windows and some rust-looking stuff at the base of the window) and we were quite concerned about the cost. We couldn't seem to find a sticker or brand name on the windows.Then I looked a little harder. I found a sticker at the very tip top of the window. I googled the name and found a distributor in the area and called to see what we should do. The man told me they are under WARRANTY! So excited about this.
We don't tend to buy 'extended warranties' on products (electronics, furniture, etc), as I've heard that if the product is going to malfunction, it's likely to happen within the bounds of the regular warranty.
However, often times products must be registered in order to take advantage of the warranty at all. Sure, it costs $0.34 (or whatever postcard stamps cost) to mail the warranty back into the company for the product, but it can be well worth the time to mail the little postcard back.