I wear through a coil cover a year through keeping the coil low and slow like you should.
Covers are a lot cheaper than a new coil...that should be your reason, but do remove it after every trip and clear any dust and dirt from inside as this might cause falsing.
I have coil covers for my (ACE 250) stock and 9 x 12 coil. For the stingler coil, I used epoxy. I got the idea from this thread: http://www.findmall.com/read.php?21,276478,276521#msg-276521 Coil still works fine, and now is protected. No worries about dragging it across sand and pea gravel tot lots.