There is no clearly defined expiration period for a child’s car seat within R44 or R129.
It is usually recommended to replace a car seat after 5 to 10 years from its production date (not purchase date). This is because materials like plastic and metal can degrade over time. The durability of a child car seat depends on many environmental factors, including prolonged exposure to strong UV rays in a car which can accelerate aging of plastic parts reducing its safe useable period.
All products have a printed production label like below that shows the month and year it was produced: