Design products, systems, and environments with enough flexibility so that they can be used and experienced by people of all abilities, to the greatest extent possible, without adaptations.

Designing flexibility into an entity increases the likelihood that the products, systems, and environments can be used and experienced by people of all abilities, to the greatest extent possible, and without adaptations. However, increased flexibility does not come free, it can entail a more complicated design, increased complexity, slower performance, and increased cost. Flexibility typically results from providing the user multiple choices, and/or adjustability-for example, providing different input/output options when operating or using a product or process. Multiple modes of signaling and communicating when providing feedback and warnings ensure that people who cannot perceive a particular signal or communications channel will be able to perceive another mode.