Let's face it. Drums take a pounding. Obviously, a drum kit gets a fair amount of action through the actual playing of a kit. Other elements such as disassembling your kit and re-assembling, weather conditions and let's not forget plain old accidents can affect your drum kit. If you're playing your drum kit regularly there's a lot of vibration constantly going through your kit. Things wear down. It's science.
The next time you change your drum skins check your drum shell carefully. First up, if you find any large cracks or damage to the shell or bearing edge itself it's best to take your shell to a drum professional who can repair this damage for you.
If you notice anything minor to your bearing edge you can probably fix it yourself easily with some fine sandpaper and a damp (not wet) cloth. Simply smooth out the damage with your sandpaper. Be very careful not to affect the profile of your bearing edge. Don't over sand. Depending on the damage you could start with a medium grade sandpaper then touch up with the fine sandpaper. After that dust your drumshell off with your cloth.
Fixing minor issues when you notice them will preserve the quality of your kit and avoid a small issue turning into a big problem later. Not only that you'll be keeping your kit sounding great!