"My advice to you is that when it comes to warranties on floor coverings you should take them with more than a grain of salt."
Ken's In-Depth Answer:
Many of my clients will ask me about warranties on various flooring products. I look them straight in the eye and explain that most of the warranties in our business are not worth the paper they're written on.
I'm mostly serious about that, but not entirely serious. What I've found is that flooring warranties will cover you for things that are never going to happen. However, they won't cover you for things that will happen, and/or things that you're rightfully concerned about.
If you've got some minor irregularities, your floor contractor can probably come and patch the floor in order to give you a flat surface. But we have to look at it first and see whether or not the floor is going to sustain an installation of these products.
Remember, a floor is something that you walk on. It takes tremendous abuse. Therefore, logic is going to tell you that the product is only going to be able to preform so much in terms of withstanding that abuse.
If you're concerned about warranties, ask for the written warranty and read the fine print. With carpet for example, most manufacturers will require that you get a professional cleaning of your carpet at least once or twice a year. You'll also have to save your receipt to prove the cleanings occurred before you make a claim. So understand the warranties and remember that in every case they're limited warranties.