Think about your question:
You keep it at home resting in a cotton cloth.
You do that because:
1) You want to protect it
or
2) You have a very dirty house
or
3) Your furniture is more valuable than the Kindle and you don't wish to get a scratch on your furniture.
If you mainly use your Kindle at home, you should (in my opinion) get something where the Kindle can slide in and out of a sleeve, such as the one here:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
I own this and I use it for my Kindle or my Kobo Glo - depending on which reader I choose to have at my bedside. Five stars and 244 customer reviews. Not too bad for a product that's less than 10 dollars.
If you will also be using your Kindle away from home (again, in my opinion), you will absolutely need something to protect your investment.