This of course depends on the condition of the seat, how much it has been used and when it was manufactured. If it is over 6 years old it is best to get rid of it. This is also the case if it is in poor condition, if it has any damage to it or if it has been involved in a road accident.
If this is not the case and the child car seat is in good condition, it can be used again. In this case, the best option is for the seat’s manufacturers to check it thoroughly.