According to some sources, we grow and change to our physical prime at around age 16 and then have a long period of gradual changes in our bodies and abilities. As we age, a broad range of environmental issues impact our abilities, such as broken bones and activity-related injuries, pregnancy, parenthood, increased responsibilities and related stresses, and caring for parents and children. During this time, many of us experience increased strength, stamina, balance and dexterity, with decreased time and conflicting demands for our attention.
Changes in vision, hearing, and memory are a common thread in our aging process. We reach a point in the growth process where a number of our abilities begin to change again, decreasing as we continue to age and grow. We adapt ourselves to the changes as we age and may not notice any difference until the environment is no longer enough to support us.
Better design for access related to these changes can alter our life experience, and the user groups and design recommendations listed here, while in no way complete, will provide a good start in this effort.
There is much overlap because, for example, the knee space that allows access at a vanity for a person using a wheelchair also provides for seated use by a pregnant woman experiencing fatigue. It can also function as a storage place for a step stool for a child. In some cases, information is repeated and in others, different sections of the chapter and book are referenced.