Closets

No idea about thenorm but I can say address the cost part of your question.

I recently redid 2 narrow, tall closets with Elfa by Container Store. Thi system offers the best value in my opinion. I choose several of the high end options and the two closets cost about $700 together.
The system is also super easy to install.

I hope that helps.

Not everyone likes Elfa because of the plastic etc.

If the poster is talking about wood type style (e.g. california closet or the various better priced same systems) - then it probably starts at $700 per closet but depends on complexity and can be multiples of that per closet. There is a lot of competition with the same materials as california closets too so no need to pay the highest price.

The Elfa system I installed in my walk-in closet cost approx. $2,000....the cost will depend on the height, width, and length.

jsey - the closets with the shelves and poles can go either way with the developer. On one place I asked the question and was told the are installed only to find out later they were not and it was too bad for me. Another place I was at did install in all the closets and a different one yet did not. Many people rip out the poles and rods to put systems in.