Handy tips to maintain your child restraint:

Haris

Check you restraints regularly,

Ensure the harness straps and headrest are at the correct height for your child. Please refer to your instruction manual on how to adjust the harness as it may vary for different models.
Ensure the top tether is secure and taut and is free from twists.
When using a lap sash in a convertible booster, the sash must cross your child’s shoulders and chest and must not come into contact with their neck or face.
Do not place your child in bulky coats, swaddles or blankets whilst they are in the child restraints. This may reduce the restraint's ability to protect your child in an accident.
Regularly check the functioning of the buckles, ensuring you hear an audible ‘CLICK’ to lock in place and regularly follow the care and maintenance of the buckle to remove any form of matter that may compromise the buckle's functionality. How to clean your buckle.
Do not leave your child in the child restraints for extended periods of time.