Durable, long-lasting furniture of differing sizes and heights is best to accommodate the different sizes and ages of preschool children. School Outfitters and DaycareAtoZ.com provide guidelines for suitable dimensions and materials for preschool furniture.
DaycareA to Z suggests investing in a variety of table and chair heights to accommodate students of different sizes. For example, 2- to 3-year old children could use chairs with an 8- or 9-inch seat height, but 3- to 4-year-olds could use a size one inch taller. Use coordinating tables that are 10 inches above the top of the chair seat so toddlers can easily reach their activities.
School Outfitters provides a chart of different size guidelines along with suggestions for chair and table types and materials. According to this website, plastic is an ideal material for preschool furniture because it is highly durable, easy to wash and also waterproof.