Please note that the listed ages for the toys are the minimum recommended ages in terms of safety and/or development as determined by the manufacturers.
As a nanny and parent, I can tell you that the specific toys that are right for your children depend on more than their age. Factors to consider include their interests, mental capacity, and physical development. I find, for instance, that many kids are unable to accurately use the shape sorters and nesting toys until age 2, although they are listed as 12 mo+ (probably because they are safely able to explore them in other ways by that age). In the same vain, many toys listed for younger toddlers may also be of interest to older siblings, especially those in the categories of imaginary play, vehicles/trains, and games.
Toys listed as age 3+ contain small parts that can pose as choking hazards so are not recommended for children under 3.
Non-plastic bath/sand toys, such as those from Hape and Plan Toys cannot be left soaking in water. Soap and sand residue need to be rinsed and left to dry after each bath/play session.
If a toy comes in contact with blood or feces, parent/guardian needs to pay for replacement of the toy (MSRP value).