CD/DVD drives these days are very reliable and have a good life span. They are getting cheaper all the time too. I wouldn't be too worried about a desktop CD drive, they are the cheapest and easiest to replace. It's when a laptop one goes faulty that you have a bit of trouble.
I use a modified file for FS2004 so I don't have to have the CD in the drive simply because I don't want the wear and tear on the CD, I don't want to go after a replacement.