The rollers along the edge of the garage door should be inspected at least twice a year and replaced every five to seven years. During your inspection, replace any rollers you find that are chipped, cracked, or worn. Most of the rollers can be removed by simply removing the brackets holding them to the door.
Inspect the tracks on both sides of the door to make sure they are free of debris and rust. You can also use a level to make sure the tracks are plumb (perfectly vertical) along their vertical sections.