DOM vs age of child?

[MasonBaby]

We currently have 2 MA, DOM 9/05 and 2/07. At times we'll use them for the two youngest kids and I was wondering if it matters which kid gets which seat. It would be when we travel to Grandma's house early next year, so the seat would be getting moved from car to car for a week. Should the baby get the newer seat or are they completely the same and it makes no difference who gets which?

[Joolsplus2]

Completely the same, as long as the kids don't balk at riding in a seat with a certain cover ;) They do expire six years from date of manufacture, but you have 2 more years to go on the older one, so no need to worry yet.