Looks like there's a lot of folks that aren't sure about fletch covers, so....he's how and why I use them.
1...they keep my feathers from dragging on anything and making noise. Being they are in a bow quiver, I can pass my bow AND arrows through the brush and clear them all at once, I do not have to get the bow through and then worry about the arrows in another carrier. With another carrier sometimes you have to look back to clear that carrier, and that is more head movement and loss of forward focus ....especially if there's game ahead you are stalking.
2....they protect my feathers from wear and tear.
3....they keep my feathers dry.
4....they hid my bright fletchings and wraps. ( I know some animals can't see color, but they can distinguish between what is bright and mute, and I don't want to wave anything bright. I wouldn't walk around with a white terry cloth hand towel hanging off my elbow for the same reason....would you?) Bright movement at close distances will give you away quicker than mute colors.
5....they add to my 'natural blind'(another reason I use a bow quiver at times)
If used properly, there is no 'flopping of cloth' till you get down to one arrow. (leave front and rear arrows in till last resort.)
I have shot, after loaning a friend a couple of arrows after a fire fight on hogs, with no arrows and the fletch cover hanging and drilled the animal.
If when you return to camp or vehicle, you will turn your bow upside down you can slide the fletch cover down the arrow shafts and you wont mat down the feathers. Yes, if you leave the fletch cover in place for a week, feathers that are making contact can mat a bit.(if I make this mistake, I just pull them in reverse with my forefinger and thumb and they come right back) You do not need to take the fletch cover on and off.
You can also 'hide' your next arrow in the rear(see pic) and its still hid but easily accessible. If your fletch cover has no bottom, its easier to remove arrows....and quieter.