New Carpet on Stairs- What to ask before selecting and getting it installed?
 

We are shopping for new carpet for our stairs, and I don't know what I need to ask or check before I buy it. Maybe you can help?

It's one flight with a turn. At the top of the stairs is a small hallway. The stairs, hallway, and the four bedrooms upstairs all have the same carpeting. I only really need new carpeting on the stairs and possibly the hallway. One day, I'd like to put hardwood floors in a couple of the bedrooms and new carpeting in the other bedrooms.

What should I look for when selecting carpet? What do I need to ask the installer before getting the work done? How will I know if the carpet is correctly installed? What other tips do you have about a job like this?

Thanks very much!