The vast majority of insert/eject problems on Apple laptops are related to how users pick up their machines. It sounds ridiculous, and some people even take offense when I offer a tutorial on how to handle their machines, but if you squash the optical drive opening, that is considered damage and is not covered by your warranty.
By picking up your laptop with two hands, and avoiding at all costs putting pressure on the optical drive area, you can prevent problems down the line. These range from failure of the optical drive, scratching disks on every insert or eject and failure of the drive to suck a disc in or spit one out.
When we see this problem, we’re often able to use a non-marring nylon probe tool to pry open the optical drive slot. These tools are thin and rectangular, and by inserting the tapered end a few millimeters into the slot and twisting, the slot can be coaxed open. However, if your optical drive is having issues and your slot is compressed, there cannot be warranty coverage for the problem.
The non-unibody 17-inch laptops are especially prone to this problem, as the optical drive is right under the wrist rest area, and the slot seems less reinforced than on other models. Plastic MacBooks are also very vulnerable. Apple, recognizing this oversight in design and engineering, made the optical drive slot in unibody laptops much more rigid. This said, you should still make an effort to avoid pressing or squeezing this opening.