Lens caps are the first line of defense for a camera's most fragile part: front caps that protect the glass from scratches, dust, and fingerprints between shots, and rear caps that shield the mount and rear element when a lens is off the camera body. The cheapest accessory in a camera bag is often the one preventing the most expensive repair.
Fit is exact - lens caps are sized to a specific filter thread or mount diameter, so match the cap to the lens's stated size rather than the camera body. For lenses that see field or travel use, a cap with a secure retention (pinch-style or clip-in) is worth the small premium over one that falls off in a bag. Rear caps deserve the same discipline as front caps; an exposed rear mount collects dust that migrates onto the sensor at the next lens change. COLAMCO supplies lens caps and basic lens protection for the camera systems business, government, and education programs maintain.