You will rarely need to use a locking clip except in some older vehicles. Built-in child restraint locking systems have been required in vehicles since 1996, and many vehicles had these features even earlier.
Always review your specific car seat manual and your vehicle owner’s manual to determine if your vehicle belts require a locking clip.
Instances that warrant use of a locking clip:
• If you have an Emergency Locking Retractor with a Sliding Latch Plate, you MUST use a locking clip to install the child restraint.
• If you have a damaged latch plate or retractor
• If your vehicle belt locks at the latch plate and your buckle/latch plate do not lay flat and stay locked/secure.
• If you own an older vehicle (model year prior to 1996).
NOTE: Although locking clips can solve a variety of installation challenges, use can be intricate and complicated. Should locking clips be misused, they can become a projectile in the event of a crash or change the crash performance of the car seat.