Not to sound like a lump on a log, but.....Surefire makes their products for hard use. So I say, use it and enjoy it!!
I consider the scratches on my user lights as badges of honor for the light. Not to mention the character it gives the light. However, it is your light to do as you please. You can use a sunglass bag. I use that for some of my custom lights, along with the aforementioned plastic storage cases. Surefire does sell some holsters. But they will swallow the E1D. I am glad you like it. If you want to customize it a little, you could get a different tailcap down the road?
This will give you a idea. This tail cap will work on your light. Currently I have it on a old school E1E. But you get the gist.
This style tail allows for easy Mouth hold. Plus it is Ti, so no metallic tastes. ha!
Another great mod is adding a GITD
zipper pull to your Defender tail cap. Makes it easier to draw from pocket.
Sample pic, so ya get the gist again!