If you think about it, disability in some form or another happens to all people (except a small number) at some point. Some may make it until the very last part of thier lives without becoming disabled at all (sudden deaths like stroke, heart attack), but for most people disability can occur at any life stage and it can be due to accident, disease or aging. So, most everyone can expect to become disabled in some way at some point in thier lives unless they are very lucky and pass suddenly from an illness or accident which does not cause a decline in ability prior to death.