Build Quality of Two Step Stair
A step stair unit can be very helpful in the kitchen or pantry to reach those items way up on the top shelf. They can assist your little ones in reaching the sink to wash their hands or brush their teeth. You can make these quite easily, they are very sturdy, and generally store out of the way when not in use.
The material construction of your step stair is going to determine how strong it is, and how long it will last. Artificial plastics and pressure formed units will have a longer life, but may be unrepairable if broken. Wooden stairs can be repaired quite easily and are the best investment, as you can do most repairs easily like anything that's constructed of wood. Meta stairs are more stable, again they are also harder to fix if they get broken, as you may have to incorporate some welding.
A 2 step stair has less reach than a 3 or 4 step unit. You loose stability as the steps get higher. meaning the 2 step unit will be less wobbly and more stable than a taller one, as the center of gravity moves up as you add steps. Taller step units can be the best choice, as they last longer, can take more damage, and generally incorporate a folding system, so you can fold them up and store them out of the way.