Wouldn't a disability at age 60 be different from one at 25? What are the age requirements for Social Security Disability?

An adult from ages 19 to 49 is considered "younger" and is deemed to have the ability to adapt to work other than the work the person has done in the past. For a "younger" person, unless certain special things are present, they must prove that they cannot do even the simplest job that exists in "significant numbers" anywhere in the United States. 

For a person from ages 50 to 54 (considered a person "closely approaching advanced age,"), they must prove that the medical condition limits them to no better than sedentary work (basically a sit down job), that he or she cannot do any work done in the previous 15 years, and that this work did not give him or her any skills which apply to sedentary work. 

For a person over 55 ("advanced age" or "closely approaching retirement age") the person must show that he or she is limited by the medical condition to no better than light work, that he or she cannot return to any job done in the last 15 years and that he or she has no work skills which could be applied to any other light or sedentary job which is similar in terms of industry, tools, and work processes to that which the person has done before.