What is the most expensive carpet?

What is silk carpet?

we used old fashioned good quality wool berber in rentals and it survived tenants regularly moving in and out and annual shampoos for about ten year and was recycled to another property when we renovated and keep in mind the depreciation rates as it should be able to be replaced more often

We have bremworth 100% wool sisal in bedrooms and on stairs. The pic of the stairs attached is carpet that has been down for 15 years. People & a crazy dog up and down them and more than one morning coffee spilled on it. It is only just starting to show a little wear now - slightly lighter parts on some of the treads.