There are four car seat stages, and steps to follow when purchasing and using a child restraint seat.
(source: Transport Canada)
The correct stage for your child depends upon their height and weight.
When looking to purchase a car seat, make sure that your child fits the height and weight limit of the seat you are thinking of buying. Use the above chart to see what is the correct stage and what type of seat your child is in need of. After your car seat is installed, be certain to send in your product registration, so that you will be notified of any product recalls.
I didn't realize that car seats had expiry dates or useful life dates until recently. Child car seats can safely be used from six to nine years depending on the manufacturer.
Be certain that your car seat performs its best. Don't use a seat which has been involved in a collision, even if it appears to be undamaged. Car seat safety starts with parents and caregivers understanding the most effective use of the different types of seats.