Why Foundation Repair are able to provide lifetime warranty

[Helen Zhang]

This question is purely for curiosity purpose, and I would like to have someone who works for foundation repair answer this question. 

I see that many foundation repair companies are now offering lifetime warranty. Why is that? and how does your company sustain overtime with these "lifetime" warranty as if the customer experience any problems with foundation, you will be called and you will have to provide the support. 

Are the piers that you install adjustable? so if soil changes, you can just tweek the piers? 

As an investor, I would like to learn about your lifetime warranty and how you are able to provide the support for it.